The guy is young and very knowledgeable and a S.A.M. graduate. There is no replacement for experience but he knows 1000000X's more than i ever will. One of the big name porters on here was one of his teachers. Granted you will lose some of the low lift numbers to get a peak flow this high BUT the average flow across the board up to .700 is what we were looking for he said.

 

suscribing, i have a similar setup in the works

 

Don't underestimate 3.62 stroke. Hard for ls1tech and 400 + inch guys to understand but that sroke is mechanically perfect for 7500 and below. Nobody's cylinder head is large enough to accomdate more than that even the ET Canted valve. The cam in this motor is to big. .680 lift is good but it should be more in the 240 range or smaller. If the exhaust flows that good I would have 1 3/4 headers and be 238/680 244/630 115. Shorter stroke applications make exceptions to get the torque and it will pay off. Example 382 (4.100x3.62)ci 500hp/500 tq 402(4.00x4.00 this sucks) 525/550 avg. on the 382 from 1800 to 6500 was 474 and you can even compare the 402 because it was to peaky.

 

Thanx for the input. Why are you saying the cam is too big? Heads that are 280-290cc and flow 390+CFM arent big enough for a 400+ motor? Why do you suggest a 115 lsa? We are using a 110. An example of another motor they did is here too somewhere. It was a ls1 383 solid roller with dart heads that did well over 800 on the motor

 

I guess it's just too hard to understand is right? There is no "mechanically perfect" stroke for 7500 and below. Does "mechanically perfect" mean slower?

The ET CV heads can peak easily over 7500+ rpm with a 4.000 stroke and even larger.

With heads like that though I do agree the cam could be smaller for sure for hydraulic roller rpm territory.

 

2 suggestions.... Been there... done that........ asked enough folks..... that know. And changed plans more than 4 or 5 times in the process.

1. Get your heads flowed on another bench. I have learned that flow numbers over 350cfm for most of us are just for braggin rights. And if they did flow that high from the shop in question..... doesnt hurt to check the number for curiousity sake. You might be suprised.

2. Smaller cam. That big port head needs velocity and the right valve event seat timing and not a stack dump of airflow at the wrong time. Keeping air in the chamber for a bit longer might help or hurt it. Duration isnt determined solely by cubic inch, but more so where the car will peak from the intake in terms of power and what it takes to make the motor act like an airpump to move the air in and out.... think of it like a turbo... it creates its own free horsepower per say at a certain point of the stroke. Rather than have all that overlap and reversion... why not use the exhaust to draw the intake charge into the intake instead or reversion pushing it out?

I had a fairly common 408 cam... didnt impress me considering what intake and exhaust was on the car. MPH was down and the dyno showed why. Made me start thinking there was a trick to this head.....

Hell.... what do I know.

Good luck.

But I can say that some of the folks I have spoke with on my build have gone above and beyond helping me understand what does, doesnt, might, and wont work.

Think of your motor like traffic..... If you could get everyone to move at a constant 40mph in synch everyone would be home on time... vs too many stops and goes going on. Cam design.... sounds like fun

 

btw, still most likely going to order a cam from ya.... but I gotta sell my old one first. I figured what the hell and might just test 2 of em.

 

So your saying that a 402 with approiate head and 4.00 bore and 4.00 stroke can make more power and torque than a 402 with 4.200 and 3.62 stroke with the same head. I think and know different and until someone can prove different, it to me is set in stone 4.00 is to much. In a racing application I would even go as far as saying that the 4.200 and 3.62 can make more power overall and per inch than any motor that was built with the 4.00 stroke like a 443 (4.200 x 4.00) for example. I'll just go back to my slow short stroke world.

Sorry to high jack thread.

 

Hp makes you haul *** not HP per inch!

Hp per inch is for ricers or someone getting weight breaks not for the real world.

4.000 X 4.200 will kick 3.62 X 4.200's ***!

 

So weight break racing is not real world, but isn't this how they determined the LSX shootout for the supercharge class and N/A class. Maybe that is why they had a small car count is because they wouldn't allow ricers to race.
I will gaurantee if they keep haveing that shootout that the smaller inch motors will in time take over. And until you build the shorter stroke engine and have proof other wise drop it.

 

Back to the original thread, did Raymac recommend you building this size engine and if they did why?

 

I asked if it would be more reliable if i went with a shorter stroke for more RPM. They said no difference as long as its set up right. I saved 1k+ not using a stroker crank and spending the money on a MUCH better valvetrain. RPM=MPH

 

same case here.. i have a light car.. no need for the extra torque... its kinda a mechanical traction control

 

Any #'s Yet

 

I am hoping to get some preliminary numbers this Monday. We have had a couple set backs with the plumbing of the direct port and we ordered the wrong balancer from ATI. I need one with an A/C belt

 

dyno #'s yet?

 

We have had rocker issues and valve float at 7300. Before then it is making 710HP 580TQ

 

Your L92 heads are flowing like hogged out LS7 heads....wow.

 

Intake Exhaust (without pipe)
.200 162 126
.300 240 180
.400 302 218
.450 316 225
.500 340 236
.550 353 243
.600 361 250
.650 369 254
.700 377 257
.750 382 263
.800 388 268
.850 395
.900 399
.950 405
1.00 414

Those are the numbers on the heads. I was wrong the first time. The cool thing is, these heads never backup. Its a great port really!

 

engine dyno?