Can Am racing

[tt 383]

OK, so does it all have to be nostalgia parts now or homologated stuff? . Surely the parts bin is better now than before?

On a side note it seems like someone could make some form of the Shadow turbo setup work now...

[hoffman900]

OK, so does it all have to be nostalgia parts now or homologated stuff? . Surely the parts bin is better now than before?

On a side note it seems like someone could make some form of the Shadow turbo setup work now...

Stock appearing. So they use stock looking heads / blocks (aftermarket) and mechanical injection. Pretty much everything is free reign and they can be very serious race pieces (55-60mm journal roller cams, lots $$$$$ in head work, etc).


https://svra.com/wp-content/uploads/201 ... 7_1.18.pdf

So 510ci max, all aluminum aftermarket block and heads as long as they look like ZL1 pieces. Mechanical injection. Anything else is free.

With the 4 cylinder stuff, where there are no aftermarket castings, power is up about 25-30% for a front running engine vs a front running engine from the day. That’s all in better understanding of head / induction porting and development, valvetrain technology, and exhaust building advancements. Same box, just a lot more power. Race gas is better now too.

[hoffman900]

I’m sorry to say, but I really doubt it. I think their is some number inflation via nostalgia. My guess is around 650bhp is more accurate.

That jibes with what I've heard - maybe, maybe in the 700s for the last McLarens but not reliably. From what I can tell, the 917s probably only ever raced in the 900hp range too, despite claims of what they did on the dynos - no intercooling and pretty primitive turbos, remember. Modern appearing vintage ones are probably in the 900hp range of course - probably a lot of that due to cam and valvetrain advancements.

I saw a continuation or clone or something at a vintage race where they were advertising 1100hp with a fully "modern" big block but who knows.

I wouldn't call any of them the pinnacle of NA engine development, but they sure did work.

*edit* Oh yeah, I feel obliged to make some joke about how they might have eked out a little more power with an iron block BBC instead of aluminum ones.

I now a top running SCCA B-Prod 289ci Ford (lap records, 2nd at the Runoffs in 1970) made about 340bhp. Today, a top vintage B-Production 306ci Ford makes around 600bhp. Bill C builds those and they are badass.

Of course back then, they were stuck with the stock Ford head and intake castings, and they had throttle bore restrictions too. That 340hp engine used AIr Flow Research ported heads/ manifold, Crane for the cams (Chase might be been involved in that one by then), and the exhaust they developed was up 30hp over the Holman & Moody built system.

[hoffman900]

Here is a profile of one:

http://britishracecar.com/ScottHughes-McLaren-M8F.htm

503ci, Dart "Big M" block, Winters Foundry aluminum cylinder heads.

In-car with data-acquisition from another: https://www.youtube.com/watch?v=67EXBrsX55g

Usually the front running ones are advertised with '800hp+'.

Quote about the 1974 UMP Shadow:

“The Shadow’s Reynolds-block big Chevy engines – tuned by ex-McLaren engine builder Lee Muir – displaced 495 cubic inches and made about 735hp officially, but were thought to pump out closer to 800.

I love how the Porsches are anywhere from 1000-1500hp.

Lots of people just repeating and making up whatever, so it's really hard to say. I think 600-650 is right for a 1960s piece, 700ish by the early/mid '70s.

I found an article that quoted:

1969: Mclaren M8A 427ci 620bhp.
1970: Mclaren M8D 469ci 670bhp.
1971: Mclaren M8F 488ci 740bhp
1972: Mclaren M20, 509ci and produced an unreliable 787bhp.

As far as the dyno type, correction factors, etc. who knows. My guess is those numbers are on the higher end if dyno'ed today and a SAE correction factor applied.

[pamotorman]

i sold my last set of tin plated sleeveless bore Reynolds block pistons to geo foltz who was still building these engines . I got a email from a engine builder at mclaren as they found a lot of these parts in a warehouse and nobody there knew anything about them. ray evernham found a can am car and wanted them to build him an engine.

[j-c-c]

Related, I'm not a GM guy, but the normal spiel back in the day for the staggered FI stacks was to smooth/widen, not sure which was the prominent theory, the engines power curve. Made sense. However I just recently read that the original intake ports were different lengths in the head, and that gave two distinct power spikes. The staggered FI intakes were to balance those differences out, which did result in a smoother, easier to drive power curve.
Is my latest understanding correct?

[pamotorman]

it broadened the torque curve just like these on the GTP corvette engines

[hoffman900]

it broadened the torque curve just like these on the GTP corvette engines

Brian Kurn (currently of Roush-Yates, formerly of ECR, Hendricks, Bill David Racing, Barton) has a presentation here from working on the GM Daytona Prototype engines showing the modeling results of this: https://www.slideshare.net/BrianKurn/15 ... cr-engines (slide 13).

[peejay]

Does anyone on this site have experience with the 1960-70's Can Am engines or the current vintage Can Am cars? I have always read that the later Big Block Chevy engines were the pinnacle of N/A engine development. Of course horsepower numbers are speculative but I have seen numbers near 900 hp for some of these N/A cars with near 500 cid. Now my question: What is the pinnacle now for a comparable size N/A engine? And I am not talking about drag race engines, but something that might run in a modern-day Cam Am.

Unrestricted Cup engines were in that ballpark, with less displacement, and a 390cfm Holley and not injection and stacks.

[hoffman900]

Does anyone on this site have experience with the 1960-70's Can Am engines or the current vintage Can Am cars? I have always read that the later Big Block Chevy engines were the pinnacle of N/A engine development. Of course horsepower numbers are speculative but I have seen numbers near 900 hp for some of these N/A cars with near 500 cid. Now my question: What is the pinnacle now for a comparable size N/A engine? And I am not talking about drag race engines, but something that might run in a modern-day Cam Am.

Unrestricted Cup engines were in that ballpark, with less displacement, and a 390cfm Holley and not injection and stacks.

Yeah, well 50 (40 to the unrestricted Cup stuff as that's about a decade ago now?) years of engine development helps. I think a lot of people can't wrap their head around that 1990 was almost 30 years ago at this point...

A current production based Superbike gets around tracks faster than the current fastest vintage Can Am cars, which are faster than they were back in the day. Think about that...

[englertracing]

Do you know what we might expect hp and torque to be from a stock appearing vintage class engine? And with a 500 cid limit.

Based on trap speeds and paddock rumors, 800bhp-ish Not sure on torque. Bill would have a more accurate answer.

Here is a 565ci Can Am Chevy: https://youtu.be/IUgj3EMhXOQ

840bhp and 780lb-ft. I’m sure there are a couple better than that.

So if there is any truth to old speculation from that time period, 800 to 900 hp might have been and still is the pinnacle for NA.

dude, a pro stock is 500 inches and makes like 1300+hp
that is a pinnacle

[englertracing]

https://youtu.be/ZBNh8LMShyE

claiming 1000hp


Id be more interested in boss 494 can am deal, should have more potential that the screwed up big block chevy mess of a cylinder head.

[hoffman900]

https://youtu.be/ZBNh8LMShyE

claiming 1000hp


Id be more interested in boss 494 can am deal, should have more potential that the screwed up big block chevy mess of a cylinder head.

If that is true, then it isn’t even close to being 510ci. There is a lot of that in vintage too...

[Calypso]

Slightly off-topic, but do they use old style spicer joints in drive axles to put all the power to the ground without issues?

[hoffman900]

Slightly off-topic, but do they use old style spicer joints in drive axles to put all the power to the ground without issues?

From what I’ve seen, yep, with splined shaft.

Personally, I’d rather have a small block car in the 650hp range. Better balanced and when well driven, aren’t far off the big block cars (if not faster than all but the fastest big blocks - even at a horsepower track like Road America).