Opinions on BBF build- X275 Car

Thinking about this engine build for my 275 Mustang:

A-460 or Eliminator block
4.600x4.000
A-460 Heads
Single A-460 Intake
SV1 Carb
14-15.1
CAM???
Steve Johnson Fogger- 1-stage
MSD 7531 box


Reason for bore/stroke is that guys are telling me big bore short stroke is way to go on small radials to limit the torque. What do you guys think? I know several turbo guys who have this bore/stroke but I am definitley going NOS.

Yep, progressives allowed...Rules are as follows:

FORMAT:
This is an 1/8 mile heads-up class run on a .400 pro tree with a pro ladder. X275 is a qualified quick 8 field. Courtesy staging and autostart is in effect. There will also be another class called “The Shootout” for qualifiers #9-16, and it will be run on a pro ladder. This allows non-qualifiers to compete for additional points and a place to race. (At larger events 2 – 16 car fields or all-run format may be used)

BODY:
The car must retain its original appearance, profiles, and dimensions. Factory roof and quarter panels must be used. Aftermarket fiberglass replacement panels are limited to hood, front fenders, doors, decklids, and bumpers only. All front ends must be of factory dimensions and cannot be stretched. Aftermarket wings and spoilers are permitted. Complete stock appearing front and rear bumpers are required. A hood must cover the entire induction system. Forward facing hood scoops/ turbo or supercharger inlets are permitted.

INTERIOR:
Factory appearing dashboard, door panels, and driver seat is required. Full Carpet is required on floorboards. Factory floor pan on driver and passenger side required. Bare inside frame of car cannot be exposed. Aftermarket steering column is permitted.

WINDSHIELD/WINDOWS:
OEM glass or lexan windows are permitted.

CHASSIS:
Complete stock chassis and frame rails must be retained. Back-halved cars are not permitted. Front core support may be modified or removed. Aftermarket bolt-on replacement front K-members/sub frames are allowed (if front shocks bolt to K-member then they must be in factory location). Mini tubs are allowed. Rear frame rails may be notched for clearance. Factory wheelbase must be maintained.

ENGINE:
Maximum displacement for all engines is 588ci. Small blocks are allowed any deck height but must retain stock bore spacing. GM Big Blocks are limited to a 10.2 deck height. Ford Big Blocks are limited to a 10.3 deck height. Mopar Big Blocks are limited to a 10.7 deck height.

TURBOCHARGERS
Single turbocharger limited to 88 mm maximum. (GT55-88, Pro-Mod 88, ET-R88 or = mid/large frame turbo). Turbocharger size will be verified by measuring the housing bore at the leading edge of the impeller wheel and must maintain the contour of the compressor housing. Inducer dimensions will not exceed 3.462 inches and Exducer dimensions will not exceed 4.765 inches on MID FRAME turbos. Inducer dimensions will not exceed 3.462 inches and Exducer dimensions will not exceed 5.56 inches on LARGE FRAME turbos. The maximum diameter of the housing bore at the leading edge of the wheel may not exceed 2 mm more than the maximum allowable turbocharger size permitted. Inserts or reducers to achieve inlet or outlet dimensions prohibited. Any type of air to air or water to air intercooler permitted. Turbochargers w/nitrous oxide are prohibited except on 2-rotor, 4 cylinder, and inline 6 cylinder engines.

SUPERCHARGERS:
Cog or gear driven superchargers are permitted, must meet all factory inlet, outlet, and internal housing dimensions. Inserts or reducers to achieve inlet or outlet dimensions prohibited. Any type intercooler is permitted. Cannot combine with nitrous oxide. Roots superchargers are limited to a 10-71. Centrifugal superchargers are permitted. Screw superchargers are not permitted.

NITROUS OXIDE:
Small block is permitted to run any type multi-stage nitrous systems. Big blocks are limited to a single stage nitrous system – A single stage fogger (2 nitrous solenoids and 2 fuel solenoids) are permitted or if using a single plate then your limited to (1 fuel solenoid, 1 nitrous solenoid), and 1 purge solenoid, purge must exit engine compartment.

TRANSMISSION:
Any factory style automatic transmission allowed. Bruno-Lenco transmissions are prohibited. Clutchless manual transmission and clutch assisted manual transmissions are permitted on naturally aspirated combinations only. Electric shifters or air shifters are permitted.

INDUCTION:
Small Block combinations may run any type induction. Big Block combinations are limited to a dedicated single carburetor with cast intake.

OILING SYSTEM:
Dry sumps are permitted on all cars.

EXHAUST:
Mufflers or inserts are required on all cars except for turbo cars. Exhaust may exit underneath car or out the front fenders but must not affect timing or staging beams.

FUEL:
Gasoline only is permitted. Alcohol or E-85 or other derivatives is prohibited.

STREET EQUIPMENT:
Functional headlights, taillights and brake lights required. All headlights, brake lights, marker lights, etc must be on car and not removed for any reason. All vehicles may be towed back from their passes.

SUSPENSION:
Stock style suspension cars only (See weights below for penalty for aftermarket suspension). Four links are prohibited on all cars. Aftermarket direct replacement components such as: front control arms, rear control arms, front coil over shocks, and rear coil over shocks are permitted. Aftermarket rack and pinion steering allowed. Rear leaf springs, springs, shocks, and coil-overs may be moved to accommodate tire clearance, and do not need to be mounted in stock location. Bolt-on or welded sub-frame connectors, rear sway bars, are permitted on all cars. Wheelie bars are prohibited on all cars. Torque arms are only permitted on cars that were originally equipped from factory with it.

TIRES:
All cars with power adder must compete on a Drag Radial type tire with the following sidewall designation 275/60/15. Naturally aspirated cars are permitted to run a 28.0” x 10.5” slick, no “W” tires permitted.

Minimum base Weights:

All minimum weights include the driver.

Naturally Aspirated (small block) 2600 lbs
Naturally Aspirated (big block with standard deck height and conventional head) 2900 lbs
Naturally Aspirated (big block with tall deck height and conventional head) 2950 lbs
Naturally Aspirated (big block with standard height and big chief head) 3050 lbs

Nitrous (small block) 2950 lbs
Nitrous (big block with standard deck height and conventional head) 3250 lbs
Nitrous (big block with tall deck height and conventional head) 3400 lbs

Single YSI / F1A/6-71 Supercharger (small block) 3100 lbs
Single F1C/8-71 Supercharger (small block) 3200 lbs
Single F1R / Xi/10-71 Supercharger (small block) 3300 lbs

Single 76mm T6 Turbocharger (small block) 3000 lbs.
Single 80mm T6 Turbocharger (small block) 3100 lbs.
Single 85mm T6 Turbocharger (small block) 3150 lbs.
Single 88mm T6 Turbocharger (Y2K or GT47-88 ) (small block) 3200 lbs
Single 88mm T6 Turbocharger (GT55-88, Pro Mod 88 or =) (small block) 3300 lb

Single 88mm T6 Turbocharger (Large Frame 88) 3350 lbs

*Small Blocks with single stage nitrous system: deduct 50 lbs
* Small Blocks (NOS only) with 23 degree Chevy heads, 20 degree Ford heads, and 18 degree Mopar heads: deduct 100 lbs.
* Small Block (NOS only) non-inline valve head with more than 2 nitrous kits: add 100 lbs
* Non-Intercooled boosted cars: deduct 50 lbs.
* Aftermarket rear suspension (Ladder bar): add 50 lbs.
* Buick/Olds/Pontiac Nitrous combos will be 3250 and not exceed 588 cu inches

* V-6 Turbocharged/Supercharged/Nitrous combos will deduct 200 lbs from base weight

* Large Frame Turbo with billet wheel: add 50 lbs

Low 4.90's in 1/8th

By reading those rules how is it possible that this car is X275 legal?
http://www.dragzine.com/news/brian-goss-new-x275-mustang-raises-some-eyebrows/

All the stock mounting points are there with stock rear frame rails and he just cut the body off. Legal like that, but the question is will body be moved at all when put back on which would alter the "true" wheelbase then it wouldn't be legal.

I like the combo make sure you get the best A460 HEADS you can find. also i would probbaly go with about 13.5 14.1 compression. See you soon

A460 = conventional head

605FOX wrote:A460 = conventional head

Sure does

dfree383 wrote:600" Boss 429 headed motor with a glide.

The engine size limit is 588ci . . . . but other than that Boss heads would be an interesting idea.
Head flow info here: https://www.429-460.com/t198-ported-kaase-boss-hemi-heads-flow-test

To be honest I think a set of properly worked A460's would have the advantage.

I would look at 4.600x4.250, 565ci. Or maybe even 4.600x4.375", 582ci if the 1/8" crank step is available.
You have plenty of options to manage launch power with the 7531.

Yes, the A460 heads are considered "conventional" for the purposes of being allowed to run X275.
If they were not allowed the BBF's would be limited to CJ/SCJ/P51 heads and would not be competitive with the MANY BBC aftermarket "conventional" heads.

dfree383 wrote:572" Boss 429 headed motor with a glide.

I don't think Hemi heads would be legal. I have an inside connection on alot of Hemi stuff just don't think it would fly for these rules.

fuel wrote:

dfree383 wrote:572" Boss 429 headed motor with a glide.

I don't think Hemi heads would be legal. I have an inside connection on alot of Hemi stuff just don't think it would fly for these rules.

Hard to say that even the Kaase Boss Nine heads are not conventional. Probably more so than an A460 . . . . from the Kaase website:
"Uses all original Exhaust and Intake manifolds for Boss 429"

The A460 have more flow potential I think . . . so it doesn't really matter.

How high could you spin a 4.000" stroke engine with A460 heads feeding it?

If you go the short stroke route you need to spin it as high as possible to make up for the lack of torque vs. a larger/longer stroke engine.

dfree383 wrote:I'd think 8500 wouldn't be out of line are far as ability to spin, not sure you'd be making any more power though.

If you aren't going to spin it to 9000+ it's probably not worth giving up the displacement.

You do not spin a N20 Motor 9000 no need and with the bigger bore this thing is going to like alot of n20 i personally think it will fly with the smaller crank in it i think it will give the motor a better compression height that way it can have some great pistons for N20 the torque of the larger stroke is not needed on 275 drag radials and the big bore with good heads should be great together for getting that nitrous in and out. With the shorter stroke should keep the pistons in the bore which is good with the extra pressure N20 Puts on them. a good rod and some great pistons this motor should run very well, remember its not made to run on MOTOR its made to run on N20 and in this class you will be spraying hard and it needs to be able to take the abuse. Just Jet Up for more power and hope the parts can handle it

Thanks for the responses guys! Keep 'em coming...Hope to start the build soon...I will keep everyone updated.

I'm liking this short stroke n2o A-head deal...subscribing...

which route did you decide to go fuel ?

Good topic here. I was going this route as well for X275 but have decided to take the N/A route just to be different

LBSRACING wrote:Good topic here. I was going this route as well for X275 but have decided to take the N/A route just to be different

...you have c-heads?