Ok I am not going to get into the total of what this is about, but been batting an idea around a little and figured lets drop it in here and see what others have to say. Goal is I am looking to produce a lot more midrange torque, low end really isn't a big issue, and will still pull some higher rpms.
Rules are 472cid how you reach it is irrelevant. Iron factory heads are required, roller cams allowed, race gas allowed. So the typical idea is of coarse a 460 bored .030 or .040 over and CJ heads but I have another idea here to accomplish this and gain some serious torque but you guys can shoot me down if you want.
Start take a D9TE-BB block, 370 truck block, standard bore is 4.050, bore it .030 over to 4.080, and run a 4.5" stroke crank with a 6.7" rod and a custom set of pistons, this would give a huge stroke to improve the torque, and small bore for better flame front control and probably better combustion for more effiecent and the CID works out to 470.7 so under the limit of the rules.
So lets here were my thinking may be off on this.

 

Myth. Given a specific displacement, the long stroke is offset by the smaller piston area (less area for the expanding gasses to act against). The two effectively cancel each other out.

Otherwise, an interesting build. I'd probably massage the heads just a teensy bit to clean up the corners and transition areas, but leave otherwise alone to maintain intake charge velocity. I'd definitely use the smaller chambers and try to max out the dynamic compression. Say something in the 9.4-9.5 range just to keep it streetable.

I'm torn on the roller cam. I like the better initial velocity of a flat tappet, but I think the lower parasitic loss and eventual higher velocity of the roller is probably a better choice. I'd probably stick to something in the 255-260 adv duration range at somewhere around 110 lobe sep. I'd probably up the rockers ratio on the intake side a tenth of a point or so to max out off-idle and mid-range airflow.

I'd be very tempted to stick with the stock intake for the improved velocity over a large-runner setup like the Weiand. At most I'd probably go with an Edelbrock Performer 460 with a spacer plate to increase the plenum volume. If I had my rathers, and money was no object, it would get an EFI system setup on a massaged Victor.

Headers? The hands-down choice would be a set of Banks. There is simply no better tri-Y header out there, in both build and engineering quality. If you ever physically picked up a set and looked at them, you know what I'm talking about.

Just for grins I ran this through Desktop Dyno:
Stock small-chamber heads with minimal cleanup (basic deburring)
9.5:1 comp ratio
750 cfm carb
dual plane intake
Small tube (1-7/8" primary) headers
Comp X4 256H cam (but set to roller profile)

The numbers DD comes up with are:

RPM HP / Torque
2000 218 / 572
2500 272 / 570
3000 325 / 569
3500 374 / 561
4000 411 / 532
4500 424 / 495
5000 411 / 432
5500 379 / 362

Brad

 

ah Brad, your not catching the whole idea here, I see where you are going with streetable but I never said anything about streetable. Race gas is allowed thus I was thinking more in the 12-12.5 range for compression, cam in the 275/286 @.050 duration with around .725 lift on a 112 to 113 LSA and 2 deg advance built in.(110 ICL) probably use the smaller port DOVE heads but with the CJ 2.19/1.71 or 1.75 valve sizes and a 950cfm carb on a victor style intake. looking for mid range to upper power with a top rpm in the 7500 range.
What your missing is this is a competition engine.

to get the compression, mill the heads .036 to bring the chambers down to 69cc, run flat top pistons wil 8cc valve reliefs and zero deck the block. puts you at 12:1 compression.

 

In that case the limiting factor is going to be the heads (unless by "factory" they will let you in with some CJ's or SCJ's as long as they are "factory spec").

Will they let you touch the heads in terms of porting, or do the heads have to be virgin pieces?

Brad

 

Porting is allowed, the CJ heads are usualy allowed. major issue is factory Iron, no aftermarket iron heads allowed.

 

Oh, well... dang.

Hmmm...

Using factory flow numbers, using your 12:1 CR number, and playing with cam profiles, DD comes up with a couple of combos that make respectable numbers. All of them peak by 5500 RPM or so (a function of the factory flow numbers). I presume you can use the headers of your choice? All the sims were run presuming open race headers.

Combo with Crane 325-2S-14 hydraulic roller
Torque - 621 @3500
HP - 535 @5000

Combo with the Crane 501-2S-14 solid roller (installed 10 deg retarded)
Torque - 546 @5000
HP - 603 @6500
Note - I think this combo is pretty much blowing DD's little electronic brain. IMHO the factory heads won't support the airflow needed to make 600+ HP. Especially not at 6500 RPM).

Combo with the Ford FRPP C460 (installed 5 deg advanced)
Torque - 543 @5000
HP - 558 @6000

Brad

 

aren't you concerned with that small of a bore the intake valve would be shrouded even more than on a 4.390 bore?my cam is 268-278,.767-.770 on a 110.it's in a 9.8-1 521,but the compression should make up for the small cubes somewhat.mines got good power everywhere.it's a roller too.

 

go look at the engine masters big block 470 cid limit, Kaase ran the small bore 4.14 stroke combo and didn't worry too much about shrouding. you can notch the side of the bore for clearence and to unshroud the valve without too much issue.
Brad, I know Scott Johnson is getting his DOVE heads to support 700hp on some of the street terror strokers he has worked on so they will support it. Have you looked at his site to see what he has for flow numbers on them ported, and tried those numbers?

look at the second chart DOVE heads and see how those numbers compare to what you are using.
http://www.reincarnation-automotive....r-index-1.html

 

kaase ran scj's that move the intake valve away from the wall.

 

I know. I ran the sims presuming that you could only make cleanup-type improvements to the heads. If you can hog them out, then the sky is pretty much the limit.

Brad

 

I put your bore/stroke combo into DD with the basic setup of my engine(466 with ported D0VE's 311/186@.600), changed the compresion to 12-1, added single plane intake, 850 carb, large tube open headers and a Lunati 41605 solid cam.

Horsepower 528@5000 and Torque 590@4000

Torque stays above 500 from 2000-5000 rpm's


Now, I changed the heads to as cast iron SCJ's and come up with: 444HP@4500 and 568TQ@3000 and 3500

Next, ported SCJ's (from Scott's site) and come up with:
743HP@7000 and 659TQ@5000 being over 600LB/TQ from 3500 to 6000

 

ever thought about milling the exaust side on the stock iron's and fitinf a adapter plate makeing it a chevy big block exaust port's in my class we have to run factory iron and i have seen a truck with that done and his combo is something like this
dooe heads with BBC exaust ports
kb flat tops
stock crank stroke and rods
herbert solid roller cam around 700 lift
quick fuel 950 cfm
victor 460 major porting work done big headers
i have a simaler set up but stock c8ve-e heads but i have a 500 stroker and he kicks my butt so is it the heads and flow or?