That isn't much difference for the big increase in volume. Were the cam specs similar? I'd be disappointed if I told the owner of this engine he could pick up power by switching to 572 heads down the road and then found out that it didn't move the peak much.

I think Greg won the bet. I feel the customer should be happy with that engine. Especially with the larger dia headers in the car.

ANDY/JIM ...I guess I didn't liken this 325 head to a cnc !345! -1 let alone an 'improvement' over that head, which has proven itself to make that power. The 345 is made with the 2.25" intake. The "etc." didn't speak to 20cc TO ME anyway. I was more complimenting/pleasantly surprised than denying the possibility. Also was curious what you thought would improve power.
JIM...I never 'ran' the numbers on your 540 but I know it ran good. What was the mph/weight? If you feel it doesnt take away from this thread can you share the details of that motor? For some reason I thought it used hand-ported -1's. I agree that with a different header there would be more power but, I would think that would necessitate a cam change to fully realize more.

HardcoreB,
The only other significant info on my old (2015) 540 CID was the Best Machine spec cam 279/290 112 LSA and 1.65 T&D paired rockers. About 0.777/0.750 lift. The car ran a Ron's Flying Toilet alcohol injection. I loved that injection.
Nothing fancy.

Correction factor on these pulls was 97% so we were losing 25 hp from the correction factor. Uncorrected numbers were 885 hp. Of course, it would've been tough to hook up at the track on a 50 degree day! I think the baro was 103 kPa so air was good.

The customer wasn’t looking for a high rpm screamer.
He wanted something low maintenance.
I freshened that motor after a few seasons(250 passes), and it was like new inside.

It made peak power at 6800(918hp), and he shifted at about 7k.
Ran a best of 8.33@165 in a 2750lb car.
The 918hp was with an 1150 carb. In the car he ran a 1050 I reworked that was down about 10hp on the dyno.

The cam was 283/292-12.

I'd expect more power from 572-13 heads but I suppose if it had a cast intake and a modest cam lobe then 918 might be where it ends up.

I was pretty happy with it(and so was the customer), and the on track performance spoke for itself.

As always the MPH and Weight ALWAYS tells the true tale. Dynos are a tool not a be all end all. The 8.33 at 2750 is making decent steam sounds like Dwaynes dyno is on the stingy side if anything FWIW

I agree . Pretty good MPH at that weight.
Doug

Andy I don't see a pick up on the crank? was rhe dyno pulls with a dual-sync?

Dyno pulls were with a dual sync. I switched over to a crank trigger after the dyno session. The dual sync didn't provide stable timing so we're changing it before the car goes to the track. I'm also redesigning the oil inlet and pump bracket.

I don't think I'd feel good about recommending 572-13 heads to this customer and then have him only pick up 50 hp. If this customer switches to 572-13 heads down the road then I'd want to see over 1000 hp.

Will you still use the DS or switch to a pro billet? What EFI will he be using?

Thanks, john.

I'll use the DS but only for the cam signal. I'll get the crank signal from the crank trigger using a Holley Hall Effect pickup and a MSD four magnet wheel. I'll keep the 50 degree reference angle from the DS. They have a Holley HP ECU in the car running V5 B170. It is sequential injection using Holley injectors in the manifold runners near the ports.

Got ya.
Any reason for the MSD wheel vs your 36-1?

John.

Respectfuuly, if you can explain how these '900hp' 325cc EZ-1 low -port heads are better than a 345cc -1 then it would be easy to explain how an equally prepped set of 572-13 heads would pick up OVER 50HP. There are a few examples of 572-13 headed motors that make over 1000HP. At least one I know of came from your last engine builder! 8.6's @ 3350 on a 10.5 tire about 15 years ago. Beyond the added flow and cross-section just like you have mentioned the improved valvetrain allows 'more cam'.

It is a BB Chevy front damper pattern so my 36-1 doesn't fit.

8.60 @ 3350 would require a little over 1000 hp depending on how well the car was sorted out. I think the customer would be happy with that. Chuck didn't think 1000 hp was an issue with 572-13 heads, good compression and the right pick of cam, rockers, and exhaust.

The motor I built used the smaller 572-13cnc365 since the plan was to not rev the motor all that high.
On my bench that version of the 572-13 only flows 5-10cfm more than a 440-1cnc345.