What is the maximum HP that full ported Cs can support relative to a strong 455? I've heard of guys going real fast on ported Cs. What can full ported Cs do?

 

How much money you have?

 

There is risk and expense when using Cast iron C heads to make big power.
Look up some builds on Real Olds power were the builder just installed a large intake valve into C heads with very good results.
Rocket racing block with a mild bowl work and large intake valve would be interesting.

 

Wondering why you would spend 5k on a Rocket block only to put very mild heads on it. Doesn’t make any sense to me. You wouldn’t be making big power so why buy a Rocket block? Waste of money.

 

As Mark knows, since we've chatted about my fresh 9.5:1 468 with Cs (all new stainless hardware), I spent alot on my Cs (way too much) recently, and to get to a legit 504hp (Mondello build online), I figured I could just port and cut these as Joe did for 504hp. To buy Edelbrocks for $2k, and have to port those would be $3k+, not worth it to me as I just want to get from my 425hp to Joe's 504hp build. As Mark also knows, I bought a pair of Speedmaster heads and had my speed shop flow them. While they are actually nice heads in every respect (nice castings, very nice springs that tested strong, exhaust flow is nice, etc) the intake flow is very unacceptable, and less than iron Cs, so I offed them. So, I figure my fresh Cs just need porting to deliver some big power. Was curious though how much power ported Cs could support....

 

Guys run 10 second times in the 1/4 on ported c’s. I am using ported g’s with larger valves on a 461 with a solid roller cam that I’m hoping will get me high 10’s in a street car. Based on builds i have researched over the years 600 is doable but your gonna need compression and aggressive cam timing to achieve that.

 

Large bore
If you plan on keeping your car and racing it having a bulletproof block is never a waste of money.
Once you tire of playing with Old iron bolt on a set of Bill's Ebrocks or other aftermarket head.
Check out Milan's builds on RealOldspower large valve light porting impressive numbers

 

The person porting is the key, I have seen full weight stockers run into the 10's with iron heads with only a stocker valve job

 

People also run 10 s with un ported production Olds heads in NHRA Stock with Q-Jets and stock valve lift. A ported production Olds heads head can make 600 plus HP no problem.

 

Thank you all for the great input, I will take it all to heart. Thank you!!

 

I was going to link Milan's 500 Hp build with non ported iron heads but the dyno sheet is no longer attached to the original thread on ROP.

 

Juan Mendoza in Garden Grove can port some Olds heads up for you, and I've heard his prices are reasonable.

 

I'm pretty sure "Team Wieland" on this forum made over 500 HP on my friends dyno with production heads.

 

Milan's heads were untouched other than a larger intake valve. I think you would have found the pump gas build well thought out and executed.
What's cool about Milan is that he is not a professional engine builder but produces results as if he was one.
He has also built some High HP Olds engines and is a drag racer with quick car. The reason I added this is because I have a great deal of respect for racers and the knowledge they have gained through track testing.

 

Yes I agree, Milan is very good!

 

My 455 with ported G heads makes 530 hp however it is a little over 11:1 so I have to run e85 (or race gas).

 

At what RPM did your engine make peak HP at?

 

About 5800 rpm

 

What was the peak TQ and at what RPM?

 

Here is the print out from McCabe’s. Looks like Max torque at 3800

 

I would just say that power curve looks very real, thats a good running olds.

 

Milans 500HP un-ported factory cast iron heads.

Following the same idea with the un-ported E-Brock motor , this worked good too.

1. 4.185 X 4.250 Wiesco pistons , Eagle rods

2. .921 ceramic lifters cam is 242 (Mopar lobe .904) 256 (Ford lobe .875) @ .050 lift is .607 intake 1.7 rocker and .575 exhaust 1.6 rocker 112 LSA in @ 110

3. Porto Sonic intake , 850 HP Ultra Holley

4. 2 inch Super Comps. 10-1 compression 93 Shell fuel

5. 2.10 X 1.72 valve size

 

Actually your peak tq isn’t at 3800. It could even be more than that at a lower rpm. You always throw out the first few numbers. And I’m guessing E85 on this pull? Pretty rich otherwise.