Wide power band street bbf

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Wide power band street bbf

Post  Calypso on July 23rd 2016, 8:10 am

This is at this point more theoretical than reality due to my current life situation, so please bear with me. 

What is reality though is that I have a very decent running project -70 torino with C6, original SCJ car, missing original engine, but the rest is there. 
My plan is to build it stock looking with D0Oe-r's. Which I have with new valves, small port cleanup and porting, seems like short turns are only smoothed), 
ported iron intake (have one, in progress), 
iron exhaust manifolds, which I have.
custom solid FT cam to work with exhaust manifolds, which I have.  I don't have specs here, but if I recall, approximately 260ish @050 with wide lobe separation in the ballpark of 113-114. I think it was specced by Randy Malik for another member's 500", 10.5 comp stock looker Iron exhaust manifold, Iron SCJ project.
Exhaust will be 2.5" factory style, which I can get locally made. 
Stock SCJ carb. I have a nice one, but could cheat by using something else as it's out of sight. I do like the idea of stock carb though, mainly because of the choke. Summers here are not the hottest and if you extend the driving season to the fall, cold engine and auto trans are not the most pleasant combo without any form of enrichment. 

What would you build if you had free hands to pick the block (not that visible), Bore, stroke, compression + converter and gears? 93 Pump gas.

Driver, I don't care about the time slip. I have another car for that. I just want to rack up miles on the street. Street tires with torino weight will be traction limited so looking to compromise off the line performance towards wide power band. Would like to use lowest numerical gear ratio, that will make sense with the combo to give it some legs. Appropriate stall modern converter with minimum slip with street miles in mind. Cam is what it is, but I expect the bottom end to have an impact to driveability. If it really has to be something different, then I'll get another.

Simple 4.3" stroke with stock block would be a no brainer, sensible and straight forward. However, I'm curious what you guys with long experience would go for with free hands, if you only focused on maxing out this application.

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Re: Wide power band street bbf

Post  DanE on July 23rd 2016, 9:29 am

Your choke point will be the exhaust manifolds. After some porting, get them "Extrude Honed", use mandrel bent pipes with a "H" pipe, and a set of MagnaFlow mufflers.

With the given constraints, a 4.15" stroke would probably work best for the wide power band.

We need to know the cam specs. And include IVC. Your probably going to be around 11 to 1 with the CR, but don't know yet.

Great project, however, your going to have your ducks in a row to succeed.


Last edited by DanE on July 23rd 2016, 10:59 am; edited 1 time in total

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Re: Wide power band street bbf

Post  BBFTorino on July 23rd 2016, 10:41 am

Simple....3.00:1 gears with a tall 275 tire and a 4.5" stroke for 545/557 and a mild 2200 stall speed convertor.

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Re: Wide power band street bbf

Post  rmcomprandy on July 23rd 2016, 1:15 pm

That cam probably needs at least 501 inches for it to be considered a STREET friendly cruiser camshaft.

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Re: Wide power band street bbf

Post  dfree383 on July 23rd 2016, 1:56 pm

The cam isn't that big.
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Re: Wide power band street bbf

Post  Calypso on July 23rd 2016, 3:12 pm

Is it mostly picking the appropriate displacement or does the bore/stroke combo how to arrive to it play a meaningful part in this case.

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Re: Wide power band street bbf

Post  Calypso on July 23rd 2016, 3:44 pm

Extrude hone for the manifolds is not possible here. Thought about porting and possibly brazing some of the bolt notches, which intrude into the ports from outside to allow more metal removal, if it'll make a difference. 
Possibly brazing inside the manifold at the crooked driver side one to add a little radius to the short turn of the 90deg bend?
Not sure if that effort would be worthwhile. Any inputs?

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Re: Wide power band street bbf

Post  rmcomprandy on July 23rd 2016, 11:53 pm

Calypso wrote:Extrude hone for the manifolds is not possible here. Thought about porting and possibly brazing some of the bolt notches, which intrude into the ports from outside to allow more metal removal, if it'll make a difference. 
Possibly brazing inside the manifold at the crooked driver side one to add a little radius to the short turn of the 90deg bend?
Not sure if that effort would be worthwhile. Any inputs?

That IS pretty much a waste of time and effort. Contain your efforts toward just up-stream of the iron manifold exits.

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Re: Wide power band street bbf

Post  Dave De on July 24th 2016, 9:03 am

Calypso,
I did what you are doing about 15 years ago. Amazing how similar right down to the 70 Torino. I didnt like the results with iron manifolds and 2.5 exhaust.
Also that wont work well with a 260 duration cam per Randy's comments.

Changes to use Holley 6115 headers with straight thru 3.5" exhaust allowed it to run beyond 6k rpm.
The world felt smaller as I looked this post.
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Re: Wide power band street bbf

Post  Calypso on July 24th 2016, 10:04 am

Dave De wrote:Calypso,
I did what you are doing about 15 years ago. Amazing how similar right down to the 70 Torino. I didnt like the results with iron manifolds and 2.5 exhaust.
Also that wont work well with a 260 duration cam per Randy's comments.

Changes to use Holley 6115 headers with straight thru 3.5" exhaust allowed it to run beyond 6k rpm.
The world felt smaller as I looked this post.

What displacement did you run?

Would it have a meaningful impact (edit:with manifolds) to run 3" pipes from front over the axle and just the last stretch 2.5"?

The cam is made to be run with manifolds. I don't expect miracles though, but thought why not try to maximize within the constraints to see how well it can be made to work. I've already went through 15 years of power creep with my other car. It's still a street car with over 600hp N/A smallblock. Lots of fun, but pain to cruise. It's like sweet cake, delicious every now and then, but can't eat it every day... I want to avoid this and stick to a plan this time. Smile

Besides, my daughter will be 18 next year and will get her drivers licence. Gotta have at least one US car that kids can drive, even if it's under supervision, to move it to the next generation. The way my son handles his kart, rain or shine, he will probably be able to drive the other one as well once he gets his licence. Smile

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Re: Wide power band street bbf

Post  Dave De on July 24th 2016, 10:44 am

What displacement did you run? 4.3 stroke with 4.390 bore 521 cubes

Would it have a meaningful impact (edit:with manifolds) to run 3" pipes from front over the axle and just the last stretch 2.5"?
I dont think so, 500 cubes of air flow needs a bigger exhaust unless you want to run it to 5500 rpm.

Stroker big blocks have instant torque at the hit. Your 600 hp small block is better for a young driver where torque builds more slowly. I'm 58 and if I had my Torino the way it is now when I was 17 I would not be alive today or the car would be destroyed.

I used the Motorsports A443 cam (hydraulic FT) thats no longer available and went 11.50's with it.
Be careful on cam selection notes that are shown for factory displacements. When your engine displacement is pushed the rpm limits come down substantially.

If you want to do more research on this go to the Torinocobra.com/forum and search Indypete posts. His 545 build used iron heads D3's at first then he went to D0Oe's but with manifolds and 2.5 exhaust. The posts are 10 years ago and he had a chassis dyno curve as well.
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Re: Wide power band street bbf

Post  Calypso on July 24th 2016, 11:07 am

Dave De wrote:What displacement did you run? 4.3 stroke with 4.390 bore 521 cubes

Would it have a meaningful impact (edit:with manifolds) to run 3" pipes from front over the axle and just the last stretch 2.5"?
I dont think so, 500 cubes of air flow needs a bigger exhaust unless you want to run it to 5500 rpm.

Stroker big blocks have instant torque at the hit. Your 600 hp small block is better for a young driver where torque builds more slowly. I'm 58 and if I had my Torino the way it is now when I was 17 I would not be alive today or the car would be destroyed.

I used the Motorsports A443 cam (hydraulic FT) thats no longer available and went 11.50's with it.
Be careful on cam selection notes that are shown for factory displacements. When your engine displacement is pushed the rpm limits come down substantially.

If you want to do more research on this go to the Torinocobra.com/forum and search Indypete posts. His 545 build used iron heads D3's at first then he went to D0Oe's but with manifolds and  2.5 exhaust. The posts are 10 years ago and he had a chassis dyno curve as well.

Thanks. I'll check it out.

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Re: Wide power band street bbf

Post  Dave De on July 24th 2016, 11:21 am

Sorry for dominating here but to answer your question
What would you build if you had free hands to pick the block (not that visible), Bore, stroke, compression + converter and gears? 93 Pump gas.

You would be happy over the top with this.
D9 block, 4.3 stroke, you pick the bore 4.39 or 4.40 is common. SCJ heads for the best bang for the buck. Paint them your engine color and they will look like iron D0OE's. Select your dish piston for 10.5 to one compression, see Diamond pistons catalog. The stroker kit should use a 2.20 crank pin and 6.8" H beam rods. Using a Torker 2 intake and Hooker 6115's have Mr Malik grind your cam. This will be reliable and give you mny years of use but you will need to step up the rest of the drive line.
10" Converter in the 2800 to 3200 stall range. The C6 is going to need to be stepped up with a quicker valve body and 5 to 7 clutches in the drum.
ET streets that are 28 tall and 10.5 wide contact patch may require custom offset wheels to center them inside the well.

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Re: Wide power band street bbf

Post  rmcomprandy on July 24th 2016, 11:22 am

dfree383 wrote:The cam isn't that big.

Dave .... is this the solid flat tappet cam I did for your projected STREET Cobra Jet...?
That cam was merely around 238/242@.050"

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Re: Wide power band street bbf

Post  Calypso on July 24th 2016, 11:30 am

rmcomprandy wrote:
dfree383 wrote:The cam isn't that big.

Dave .... is this the solid flat tappet cam I did for your projected STREET Cobra Jet...?
That cam was merely around 238/242@.050"

I think it is. Seems my memory is not that great. Will get the accurate numbers later. Sorry for the misinformation... Embarassed

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Re: Wide power band street bbf

Post  dfree383 on July 24th 2016, 11:58 am

rmcomprandy wrote:
dfree383 wrote:The cam isn't that big.

Dave .... is this the solid flat tappet cam I did for your projected STREET Cobra Jet...?
That cam was merely around 238/242@.050"

Yes it is
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Re: Wide power band street bbf

Post  rmcomprandy on July 24th 2016, 12:23 pm

dfree383 wrote:
rmcomprandy wrote:
dfree383 wrote:The cam isn't that big.

Dave .... is this the solid flat tappet cam I did for your projected STREET Cobra Jet...?
That cam was merely around 238/242@.050"

Yes it is

I looked-up past records and that camshaft for your Cobra Jet engine had the specs:
.875" MINIMUM tappet diameter; aggressive lobe flanks -
265/280@.020" - 238/242@.050" - 150/152@.200" - .346"/.338" lobe lift -
.598"/585" theoretical gross valve lift with 1.73/1 rocker arm ratio -
114 degree separation; 112 intake lobe centerline

Valve guide height modification IS necessary on O.E.M. cylinder heads.

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Re: Wide power band street bbf

Post  Calypso on July 24th 2016, 12:31 pm

Just checked the card and you're right. It was the .020 duration which came out...

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Re: Wide power band street bbf

Post  Calypso on July 24th 2016, 1:41 pm


Valve guide height modification IS necessary on O.E.M. cylinder heads.

Thanks for the input. The heads have new valves and viton type seals. Haven't seen how stock guides would compare. Will check the height at installation.

Considering the application and the accurate cam specs, what displacement would you go for?

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Re: Wide power band street bbf

Post  rmcomprandy on July 24th 2016, 1:47 pm

Calypso wrote:

Valve guide height modification IS necessary on O.E.M. cylinder heads.

Thanks for the input. The heads have new valves and viton type seals. Haven't seen how stock guides would compare. Will check the height at installation.

Considering the application and the accurate cam specs, what displacement would you go for?

440 to 470 size street engine was the design parameters of that camshaft.

A 501 cubic inch engine, (4.150" stroke), is the biggest I would go, unless off-idle response is your target.

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Re: Wide power band street bbf

Post  Calypso on July 24th 2016, 3:03 pm

rmcomprandy wrote:


440 to 470 size street engine was the design parameters of that camshaft.

A 501 cubic inch engine, (4.150" stroke), is the biggest I would go, unless off-idle response is your target.

Would you see a meaningful difference between large overbore 3.59 stroke vs. basically stock 460 bottom end?  Is it mainly cid difference you would see, or would that shorter stroke give the engine different nature?

I haven't yet opened the current engine the car came with to see what stroke it currently is. Stock early 460 cranks are not easy to come by here, so bigger displacement short stroke engine build might not be that impractical, if I need to get forged pistons new anyway. Truck rods I can find very reasonably.

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Re: Wide power band street bbf

Post  rmcomprandy on July 24th 2016, 6:53 pm

Calypso wrote:
rmcomprandy wrote:


440 to 470 size street engine was the design parameters of that camshaft.

A 501 cubic inch engine, (4.150" stroke), is the biggest I would go, unless off-idle response is your target.

Would you see a meaningful difference between large overbore 3.59 stroke vs. basically stock 460 bottom end?  Is it mainly cid difference you would see, or would that shorter stroke give the engine different nature?

I haven't yet opened the current engine the car came with to see what stroke it currently is. Stock early 460 cranks are not easy to come by here, so bigger displacement short stroke engine build might not be that impractical, if I need to get forged pistons new anyway. Truck rods I can find very reasonably.

With this type usage, it is simply about cylinder volume, head capability and the RPM relationship.

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Re: Wide power band street bbf

Post  Calypso on July 25th 2016, 12:46 pm

Thanks!

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