532 stroker build for a cobra

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532 stroker build for a cobra

Post  lvhdude on January 19th 2013, 9:32 am

I'm building a FFR MK IV Roadster (cobra replica) and am thinking 523 stroker from a DOVE-A Block. 4.44 bore and a 4.30 stroke. This will be my first BBF build, tho not my first engine build. So here's my goals. Pump gas, dependable, reasonable (yeah right) on fuel, like to have cruise rpm around 2000 at 70 in OD on a 5 spd, .69 OD (I think) 3.55 gears and 26" tires. I like the lumpy idle and sharp crack of big cams and high compression but driveabilty is a real concern. I've built engines that ran great at full throttle, but were crap at lower rpms and loads and a pain to keep up on the cam. I like the idea of a spreadbore carb so as to be on the lean side on the primaries, and make up for that with being fatter on the secondaries to make good power when the right boot is planted. I wonder about 2 fours opposed to a single 4bbl, thinking that the front carb primaries could be jetted the same way (a little leaner) and make it up on the secondaries with the rear carb on progressive linkage. Dual plane or open single quad manifold? I'm pretty sure most dual quad manifolds are open plenum. Maybe I'm over thinking all that. I have an idea that bigger cubes are always better to start with, may allow a little less compression/cam and still make tons of torque at low and midrange rpm. Are ported heads a good idea? Or can I have too much flow and too big of valves to make good torque on the bottom end? I have this theory that Torque is really what makes a car a hoot to drive on the street, more so than big HP numbers at maximun RPM that sacrafices the real useable range for a daily driver, well at least a car that would be fun on road trips like the California coast. I'm sure you guys see a lot of requests like this, so please bear with me. And I'd like to thank all in advance for helping to educate me. I look forward to your suggestions and ideas. Thanks, Joe


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Re: 532 stroker build for a cobra

Post  dfree383 on January 19th 2013, 9:44 am

A 9.5-10:1 Aluminum headed 4.300 Stroker is more than enough to scare you to death in a little Cobra.

.030 Over Bore with a 4.300 crank, some 6.8 Hbeams and a set of dished forged pistons.

I'd do a decent sized hydraulic roller for low maintence, the are not good for big RPM in a BBF due to the geometry but for under 6000ish rpm type street cruiser that you looking to lope along at 2000 rpm @ 70mph in OD they will be fine.

Id look at a set of Kaase P-51's or Ford Racing SCJ heads and a Torker 2 intake with a 950 hp as a top end. the intake will give you hood clearance and operate well in the range.
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Re: 532 stroker build for a cobra

Post  lvhdude on January 19th 2013, 9:53 am

So .030 over bore instead of .080? I have the headers from FFR that fit the standard 385 series heads. I was under the impression that true SCJ heads have a different ports and manifolds and headers are difficult to find, read expensive. Am I misinformed? I know the P-51s have standard ports. I'm kinda an adrenalin junkie, so "scared to death" kinda power is perfect! Thanks!

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Re: 532 stroker build for a cobra

Post  dfree383 on January 19th 2013, 10:03 am

Yes .030 leave the the cylinder walls thick, its not worth the little bit of gain.

Actually there are 3 different exhaust parts on factory heads. 1st is the factory passenger stuff, then the bigger SCJ/CJ ports the you have EFI ports on Trucks and Vans.

Check with FFR and see which headers you have as long as the headers fit the Factory SCJ heads they should work fine, the P-51 stuff is raised slightly, but it shouldn't be an issue.
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Re: 532 stroker build for a cobra

Post  2fox on January 19th 2013, 10:43 am

.030 over with 4.300 = 521 cubes
.030 over with 4.500 = 545 cubes

Am subbing here also. Did you just but the cobra recently?

Iam new to. To the 385 series engines.this is my first 385 build. I'am a "or was " A 408W and BBC man.

Iam just still debating on heads my self. So I can get my stroked kit.
I think? Not sure that the 4.300 may give you a better stronger piston package, am not sure if the piston pin would be in the oil ring lands or not? I'm just going. 030 over with my C9 block which I hope checks out good.
someone let.US know about the 4.300. & 4.500 strokes here. About the pistons if the piston pins are in the oil ring package or not? I I would scarifice stroke for a stronger piston. And one with a big Piston Crown. At least .300-..350 thick

Very nice plans you have there.we had a cobra down here for sale. It's Red . It had a 428 in it with edelbrock RPM alum.heads.the valve covers said 427 on them ..way to go to make it look real..my bro inlaw was going to buy it. But the man wanting more the 22,000 for it. Would gave him more. But it handled like it was driving sideways.you couldn't even get on of cause it was so scary just to go 50 MPH slowly in it.
Good Luck Joe. And welcome to the site Enjoy. Gary


Last edited by 2fox on January 19th 2013, 10:47 am; edited 1 time in total (Reason for editing : to many typos tried to get most of them out.sorry my wording is Not Good by far.)

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Re: 532 stroker build for a cobra

Post  lvhdude on January 19th 2013, 11:04 am

Thanks Gary. It seems the 4.3 stroke gives a bit better rod angle? And seems to not require block clearanceing (not a big deal) Better angle = longevity in my little pea brain. Yes, took delivery of the kit in November. IRS rear suspension, (8.8 Lincoln donor center section), Koni coil overs, tubular adjustable control arms.

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Re: 532 stroker build for a cobra

Post  2fox on January 19th 2013, 11:59 am

lvhdude wrote:Thanks Gary. It seems the 4.3 stroke gives a bit better rod angle? And seems to not require block clearanceing (not a big deal) Better angle = longevity in my little pea brain. Yes, took delivery of the kit in November. IRS rear suspension, (8.8 Lincoln donor center section), Koni coil overs, tubular adjustable control arms.
yes rod to stroke.ratio another issue the shorter the better if I recall in my pea size brain.
.so you got a kit? If so are does the oil ring.go through the piston pin?
You're Welcome..people.don't awnser me.to much here. Cause of.my typos and grammar skills. Sad.world.isn't it.

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Re: 532 stroker build for a cobra

Post  rmcomprandy on January 19th 2013, 12:26 pm

A 5 speed transmission with a 385 stroker engine is about useless to have all those speeds and it will constantly break if driven really hard, (of course some people like to just tool around and smile).

Get a STRONG 3 or 4 speed transmission, you will be glad you did.

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Re: 532 stroker build for a cobra

Post  2fox on January 19th 2013, 1:04 pm

From my experience with AC cobras are people just like the standard trans. My bro inlaw that was going to buy that one a told you about wanted me if he got it to install the shifter handle thats bent and goes way up by the radio. LOL.
me now I hate standards. Signs that aurirightis has gotting to me.

You should have a super fast Cobra there even with the 5 spd. Shouldn't even need open it up all the way.

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Re: 532 stroker build for a cobra

Post  lvhdude on January 20th 2013, 7:31 am

2fox wrote:
lvhdude wrote:Thanks Gary. It seems the 4.3 stroke gives a bit better rod angle? And seems to not require block clearanceing (not a big deal) Better angle = longevity in my little pea brain. Yes, took delivery of the kit in November. IRS rear suspension, (8.8 Lincoln donor center section), Koni coil overs, tubular adjustable control arms.
yes rod to stroke.ratio another issue the shorter the better if I recall in my pea size brain.
.so you got a kit? If so are does the oil ring.go through the piston pin?
You're Welcome..people.don't awnser me.to much here. Cause of.my typos and grammar skills. Sad.world.isn't it.

I have not yet purchased a bottom end kit. Have been doing reading on what's available and I believe stroke gives better torque numbers than big bore alone. But like bore don't want to go to the maximum and sacrafice longevity. Most of what I read suggests that the DOVE-A blocks will easily stand .080 bore (sonic test to confirm). And the 4.3 stroke may live better than the 4.5 out in the real world, (well extended street use).

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Re: 532 stroker build for a cobra

Post  dfree383 on January 20th 2013, 7:37 am

lvhdude wrote:
2fox wrote:
lvhdude wrote:Thanks Gary. It seems the 4.3 stroke gives a bit better rod angle? And seems to not require block clearanceing (not a big deal) Better angle = longevity in my little pea brain. Yes, took delivery of the kit in November. IRS rear suspension, (8.8 Lincoln donor center section), Koni coil overs, tubular adjustable control arms.
yes rod to stroke.ratio another issue the shorter the better if I recall in my pea size brain.
.so you got a kit? If so are does the oil ring.go through the piston pin?
You're Welcome..people.don't awnser me.to much here. Cause of.my typos and grammar skills. Sad.world.isn't it.

I have not yet purchased a bottom end kit. Have been doing reading on what's available and I believe stroke gives better torque numbers than big bore alone. But like bore don't want to go to the maximum and sacrafice longevity. Most of what I read suggests that the DOVE-A blocks will easily stand .080 bore (sonic test to confirm). And the 4.3 stroke may live better than the 4.5 out in the real world, (well extended street use).

Do not expect any block to easily go to .080 over. They all need to be sonic tested when you start getting over .060 in any type of performance application.
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Re: 532 stroker build for a cobra

Post  lvhdude on January 20th 2013, 7:38 am

rmcomprandy wrote:A 5 speed transmission with a 385 stroker engine is about useless to have all those speeds and it will constantly break if driven really hard, (of course some people like to just tool around and smile).

Get a STRONG 3 or 4 speed transmission, you will be glad you did.

You may be right. I have broken a number of 4 speeds, both T-10s and top loaders, tho never a big spline top loader.

The TKO's are rated up to 600 ft lbs of torque, and that would be pretty hard to actually load that much in a 2600 lb car, I think, less tubbed and some pretty beefy wrinkle walls. I plan to run Avon 285/40ZR 17s on the rear. Plenty of T-5s out there smoking street tires on Mustangs, but again I think the slicks would overload them pretty quick. While I may make a few 1/4 mile passes, this will primarily be a road car.

Thanks for the tip tho.


Last edited by lvhdude on January 20th 2013, 7:41 am; edited 1 time in total (Reason for editing : spelling)

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Re: 532 stroker build for a cobra

Post  lvhdude on January 20th 2013, 7:50 am

2fox wrote:From my experience with AC cobras are people just like the standard trans. My bro inlaw that was going to buy that one a told you about wanted me if he got it to install the shifter handle thats bent and goes way up by the radio. LOL.
me now I hate standards. Signs that aurirightis has gotting to me.

You should have a super fast Cobra there even with the 5 spd. Shouldn't even need open it up all the way.

They do go forward some, however it puts the shift knob just about in the right spot. It's the same shifter typically used on factory 4 speeds of the period, except turned forward as you are actually sitting forward of the rear of the trans. shifter handle doesn't know from which direction it is pushed or pulled, however it's never going to be a Hurst Supershifter. There are some shifters that can be remote mounted forward of the actual one located on the trans. Sort of a short version of a VW Bug setup, and it would appear, much more solid. Agreed, the forward setup may not be the best for a competition car, but it was good enough to smoke a lot of competitors in it's day.


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Re: 532 stroker build for a cobra

Post  rmcomprandy on January 20th 2013, 11:21 am

lvhdude wrote:
rmcomprandy wrote:A 5 speed transmission with a 385 stroker engine is about useless to have all those speeds and it will constantly break if driven really hard, (of course some people like to just tool around and smile).

Get a STRONG 3 or 4 speed transmission, you will be glad you did.

You may be right. I have broken a number of 4 speeds, both T-10s and top loaders, tho never a big spline top loader.

The TKO's are rated up to 600 ft lbs of torque, and that would be pretty hard to actually load that much in a 2600 lb car, I think, less tubbed and some pretty beefy wrinkle walls. I plan to run Avon 285/40ZR 17s on the rear. Plenty of T-5s out there smoking street tires on Mustangs, but again I think the slicks would overload them pretty quick. While I may make a few 1/4 mile passes, this will primarily be a road car.

Thanks for the tip tho.

I have driven at least 20 Cobra kit cars, (probably more but, I am being conservative), with all different engines of different modifications. Any of them with a big block, (even a non-stroker 460), I would eventually start in 2nd then went directly to 4th and hardly ever used 1st, 3rd or 5th. A 306 engine is an entirely different story, LOL.
If it was mine, I would use even the shorter 4.150" stroke in that engine.
To me, the whole point of having a Cobra kit car is the FTD, (fun to drive), factor.

Be real careful about detonation as lugging the engine, (it will take any amount of throttle you give it until the tires spin and will have enough torque to weight ratio to lug it easily around any slow speed turn), will eventually destroy it.

How far can you spin the tires...?

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Re: 532 stroker build for a cobra

Post  lvhdude on January 20th 2013, 3:42 pm



How far can you spin the tires...?[/quote]

Good point

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Re: 532 stroker build for a cobra

Post  maverick on January 20th 2013, 4:03 pm

I've had a few T-5's...they left me unimpressed. J.m.o., but I think a stroked BBF will make a T-5 seem like it was made of glass.
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Re: 532 stroker build for a cobra

Post  dfree383 on January 21st 2013, 5:43 am

a TKO-600 or a T-56 Will Live behind a BBF in a Cobra. I wouldn't waste the time with a T5 or most Factory 4 speeds.
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Re: 532 stroker build for a cobra

Post  lvhdude on January 21st 2013, 6:03 am

Transmissions are easy enough to change or update, thanks for the input there. Gears and tires the same. I was really looking for suggestions and ideas about an engine. Theory about head flow as to streetability, cams, carbs, induction opinions etc. So far, a shorter stroke and less bore. It's been suggested that .080 over would not be a good idea, and that 4.3" stroke is too much. .080 over would need to have the block filled to the water pump holes to make it strong enough. Is that common for a street motor? Am I missing something in thinking that more cubes is just better in general, that around 10:1 compression is about max for pump gas, and too much air flow in the heads may hurt the low and midrange performance? single carb vs dual quads? I guess a stock 460 with a 2 bbl might be REALLY reliable, but I am kinda willing to be somewhat more adventurous. I know there's lots of choices of parts, I guess I'm looking for a good combination of performance and longevity, but I have no illusions of a 100K mile motor makeing 900 HP and 1000 ft lbs tq. Something between those two maybe?

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Re: 532 stroker build for a cobra

Post  dfree383 on January 21st 2013, 6:12 am

A bigger motor is going to make more torque and blow the tires off even harder.

Any of the current factory style quality after market heads Like P-51's, Ford Racing SCJ, Blue Thunder, TFS streets or Edelbrocks will get the job done for a cool and fast street ride and a 501-521" motor is plenty.

You just can't use all the power you can make in one of those cars.

You should be able to build a nice 500-600 hp motor that will last a real long time if you don't abuse it or rev the piss out of it.



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Re: 532 stroker build for a cobra

Post  rmcomprandy on January 21st 2013, 12:50 pm

Just an observation; if I had my choice of any engine to have in my Cobra kit car, it would be a FRPP 392 crate motor with the "Z" heads #M-6997-C392FT. It just seems to fit the package REAL well without to much front end weight giving great handling for fun road race track events.

The big block is usually the "eye catcher" though.

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Re: 532 stroker build for a cobra

Post  2fox on January 21st 2013, 1:11 pm

rmcomprandy wrote:Just an observation; if I had my choice of any engine to have in my Cobra kit car, it would be a FRPP 392 crate motor with the "Z" heads #M-6997-C392FT. It just seems to fit the package REAL well without to much front end weight giving great handling for fun road race track events.

The big block is usually the "eye catcher" though.
that might be a good a idea I got a alum headed 408W street motor going up for sale real soon. Just 4000 miles in about. 4 oil changes already. Street solid roller cam rpm intake
Roller rockers with stud girdle. I'm going 521/545. Just like you want. Smile

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Re: 532 stroker build for a cobra

Post  quick 52 on January 21st 2013, 4:42 pm

There is a red one that hang's out at the shell down on woodward a old timer with one leg has it... has a fe 480ci in it and flat out runs been to the track a couple times and its runs easy 10.0 @ 145 granny shifting it got 9.50's in it drives it all over sweet car.

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Re: 532 stroker build for a cobra

Post  DanH on January 21st 2013, 4:55 pm

2fox wrote:
rmcomprandy wrote:Just an observation; if I had my choice of any engine to have in my Cobra kit car, it would be a FRPP 392 crate motor with the "Z" heads #M-6997-C392FT. It just seems to fit the package REAL well without to much front end weight giving great handling for fun road race track events.

The big block is usually the "eye catcher" though.
that might be a good a idea I got a alum headed 408W street motor going up for sale real soon. Just 4000 miles in about. 4 oil changes already. Street solid roller cam rpm intake
Roller rockers with stud girdle. I'm going 521/545. Just like you want. Smile

why not a Cleveland ? build it for the power you want and it does have the Big Block look

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Re: 532 stroker build for a cobra

Post  IDT-572 on January 21st 2013, 6:46 pm

If I were doing one it would be a 514 or 521 with a set of TFS Streets @ 10:1 compression, torquer two intake,
good hydraulic cam, just small enough to make it drive nice.

The small runner intake of the Streets and good combustion chamber would make a killer street engine. (small runners and big cube's make good torque, and the TFS heads flow well enough to make good hp too).

And you can run the primary's lean and the secondary's fat to make the total AFR right under full throttle and still have good fuel milage, well as good as a BBF will get in a light chassis. Just don't lug it too hard in the higher gears and low rpm.

WOT will be a very short event when ever and where ever you choose to do it. Twisted Evil

JMHO
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Re: 532 stroker build for a cobra

Post  Lem Evans on January 21st 2013, 7:09 pm

IDT-572 wrote:If I were doing one it would be a 514 or 521 with a set of TFS Streets @ 10:1 compression, torquer two intake,
good hydraulic cam, just small enough to make it drive nice.

The small runner intake of the Streets and good combustion chamber would make a killer street engine. (small runners and big cube's make good torque, and the TFS heads flow well enough to make good hp too).

And you can run the primary's lean and the secondary's fat to make the total AFR right under full throttle and still have good fuel milage, well as good as a BBF will get in a light chassis. Just don't lug it too hard in the higher gears and low rpm.

WOT will be a very short event when ever and where ever you choose to do it. Twisted Evil

JMHO

Given the hood clearance issues with a BBF in a Cobra kit, the tq'er II manifold would help a lot. Moving peak tq. a little higher could help make the car more drivable on an unprepared surfice also.

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