How to build the best 8000 rpm Ford small block

[blykins]

425hp isn't much for a high revving SBF. I'd go with a big bore, short stroke combo, like you say, maybe a 331/347. I wouldn't trust a factory block for very long turning 7500-8000 making over 400hp. I would go with an aftermarket block if you plan on staying at WOT for periods of time.

Of course making that kind of power at that high of rpm would basically mean that the engine would be somewhat turdish on the street.

However, to get there on sort of a budget, I'd go with a set of AFR 205/225cc heads, a large solid roller camshaft, and a large single plane intake, like a Super Victor. As the others are saying, you're gonna need to spend a lot of money in the valvetrain area. Light valves, titanium retainers, locks, stud girdle, etc.

With that combination, you'll overshoot your 425hp goal by quite a bit....another reason to not use a stock block.

[Bryan Wilson]

Sounds like you need a V8 Super car engine 600hp on the 7k rev limiter all day like at Bathurst can be done big dollars though.
Cheers,
Bryan

[Alan P.]

The motor will be for track use only but run on pump gas. A TWM style velocity stack fuel injection unit will be used. I agree that a solid lifter valve train will need to be up to task and AFR heads would be a good start with a Dart block or equivalent with 4 bolt mains.From what research I've done it would appear that a 331 motor would be as large a displacement motor that I would want to go and still achieve the high RPM's.

[LoBelly]

Originally Posted by Alan P.

...From what research I've done it would appear that a 331 motor would be as large a displacement motor that I would want to go and still achieve the high RPM's.

firstly - ditto

secondly re: your 331 engine displacement - are you confusing stroke with displacement? Stroke is important in high revving engines because the longer the stroke the faster the piston has to travel to get from the top to the bottom - the higher the piston speed the more stress on it (the piston) when it has to change direction.

If you go to one of the after-market blocks with a 4.125 bore then a 3.25in stroke will give you a 347 (i think) whereas at 4.03in bore the engine would be a 331.

Traditionally the higher revving engines were nicely over-square (bore>stroke) and conventional (historic) theory held that having the stoke at 75% of the bore was the optimum level (like the 302).
However with the superior parts and materials today I'm not sure that that holds.

Just FYI there is guy in our club who regularly runs his 347 up to 8k (solid cam) and he also built the engine for another club member who's shift point is set at 7400rpm on his hydraulic cam windsor 302 - both are EFI running Edelbrock heads/manifold and both are regularly street driven and exhibit very sociable behaviour. I would guess premium ULP.

I'm just saying this so you know that what you're after isn't really that unusual - it's just a bit pricier.

Have you got that book on performance windsors? A bit dated now but lots of info to help you balance the pros & cons of different configurations.


LoBelly

[Cobra #42]

Alan P, Don't know where you are located but Keith is excellent in building all types of motors, but he really good on race motors. Keith is a racer and drives what he builds. I think he would also tell you that you might get a better performing road race car if you looked at the torque and not so much the revs. Don't know your background in road racing but the less time spent of shifting and the more time driving the car will get the results you want. Also don't just look at the motor, having a car that has a great suspension and being able to put a good setup on the car is very important. Invest in your brakes and your lap times will drop. Don't mean to preach but also invest in yourself, practice and work with your team to make the car go fast. If you need any help drop me a email. don@texasdrivingexperience.com See you at the track, db

[CobraEd]

There are a lot of 400hp 302s out there. With the heads and cams available for them today that is an easy number to reach.

So, I would say that if you are gonna take a small block and stroke it, . AND run it to 8,000 rpm, you could be looking at 550 hp at the crank.

But then, . . . what do I know.


.

[Alan P.]

Originally Posted by Cobra #42

Alan P, Don't know where you are located but Keith is excellent in building all types of motors, but he really good on race motors. Keith is a racer and drives what he builds. I think he would also tell you that you might get a better performing road race car if you looked at the torque and not so much the revs. Don't know your background in road racing but the less time spent of shifting and the more time driving the car will get the results you want. Also don't just look at the motor, having a car that has a great suspension and being able to put a good setup on the car is very important. Invest in your brakes and your lap times will drop. Don't mean to preach but also invest in yourself, practice and work with your team to make the car go fast. If you need any help drop me a email. don@texasdrivingexperience.com See you at the track, db

Don, I do appreciate your input, but with my experience as a BSR driving instructor over the years, I have found that fewer shifts would be better accomplished with a higher revving motor as has been done with both Ferrari Porsche and BMW. Those makes have done pretty well with that format ,high RPM , good HP, not torque.MHO.