cutlassefi

Hey guys,
Did a Procomp headed 374 Small block yesterday. I'll post the dyno sheets but here are the specs;
4.125 DSS Racing forged piston
Scat 6.00" I beam rods
Base Procomp heads, no port or bowl work, 2.07/1.68.
Performer RPM with divider cut
Quick Fuel 735 VS carb 71/84 jets, (stock is 68/80). Reduced secondary HS air bleeds from 33 to 31.
9.5:1
Custom Lunati Hyd Roller, 223/231@.050 on a 112lsa
1.6 Stainless Roller rockers
5/16 .120 wall restricted pushrods
7qt. Canton deep pan
Melling HV pump with purple spring
330 crank stroked to 3.500
Internally balanced

Manifolds;
382hp/408tq
Headers;
411hp/430tq

Run on 89 octane with both exhaust systems blowing thru pipes and Magnaflow mufflers. Thanks!!

jmcghee

Sounds like that would be perfect for my 64 convertible.

oldsmobiledave

Well played sir.


Cost to build?

oldcutlass

What's the lift on the cam?

cutlassefi

.547/.541 I believe.
9K+. Customer supplied valve covers and manifolds.

cutlassefi

Pics. Thanks.

oldsmobiledave

Curious why you stopped the pulls at 5500 rpm?

cutlassefi

I did one to 5700 with an air cleaner installed. It quit making power at 5500.
If you look at the header dyno sheet you'll see less than 1 hp difference between 5400 and 5500. That normally tells you it's pretty much done.
Thank you for the thumbs up btw.

Oldcoyote

I love these posts. What is the source of the stroker crank and have you ever put one in a 403?
thank you

olds 307 and 403

This is just an offset ground 330 crank according to Mark's list. Very nice street build. 30hp and tq with headers over manifolds.

oldsmobiledave

29 hp & 22 TQ actually (not 30 & 30) but still shows the value of headers.

cutlassefi

Not so fast. At 5500 it's about 29lbft as well��
But yes it does show the value of headers. More power across the board with no loss anywhere.

cdrod

Hey Mark:
Tell me about cutting the divider in the Performer manifold. What are the benefits? Does it help low-end or top-end performance. How much is removed? Thanks

Rodney

cutlassefi

Last time I did a back to back it was about 5-8hp above previous peak. It does not hurt it anywhere else.
I normally cut them 3/4"-1" depending on the depth of the plenum.

olds 307 and 403

Makes sense kind of like an x pipe for the exhaust, helps feed the cylinders more evenly.

AZ520

I just dropped off a 1972 olds 350 to my machinist, he is doing short block tear down and build if is buildable. It was a 150 dollar craigslist find. It still had the nylon timing gear, never been opened up. I have been reading about these stroker builds using small journal chevy rods and offset grind the crank to 3.5. I would love to get a 370 olds, but have a budget of about 2,000 for the short block.

AZ520

Is it possible or am I dreaming

olds 307 and 403

The journals on the crank need offset ground and widened. Figure in that plus the cost of the 2" journal sbc rods and sbc 400 pistons. The rest will be normal machine work.

ELY442

That's a small cut. I see other manifolds that has a pre cut divider that has a larger cut than yours. Any benefits from that?

cutlassefi

Dunno, never tested those back to back but I would imagine any cut at all would be beneficial.

cutlassefi

Final numbers. Both were done after running the temps up a bit. Thinner oil means more power.
415 is 1" Wilson 4 hole tapered spacer. 417 is 1" open spacer. Any idea why they didn't make much of a difference?
Thanks.