mebirkle

Hi,

My oil pump seized on my stock block and I happen to have a built 331 block ready to go into the car. It is a SCAT setup with Keith Black heads flat top with slight recesses and almost 0 deck.

I am currently running Edelbrock Performer heads which are quite small on the stock block and would like to know if moving these over to the 331 makes any sense at all or should I just go with new heads and a bigger runner size?

Here are the specs existing specs on my current heads:

http://www.summitracing.com/parts/EDL-60379


Combustion Chamber Volume (cc):60
CNC-Machined Combustion Chamber:No
Intake Runner Volume (cc):170cc
Exhaust Runner Volume (cc):60cc
Intake Valve Diameter (in):1.900 in.
Exhaust Valve Diameter (in):1.600 in.
Maximum Valve Lift (in):0.575 in.
Outside Diameter of Outer Spring (in):1.460 in.

Everyone I talk to says that these heads will choke out the 331 due to the small runner size.

I have been advised by the person who is working on the new setup to go with 210 runners with new heads, but that seems way to big for a 331. Everyone else that I talk to says that I should stay around 185 runners. Any thoughts on runner size? I plan to reuse my x-CAM if that matters to anyone.

Thanks so much...I hope the ask makes sense.

Should I reuse my heads? If so, what are the drawbacks?
Should I get new heads? If so, what size runner should I go with to be safe so I don't lose bottom end?

Duncan_GT

I would look more towards a 170 or 190 TFS head

reldla1996

For what you're talking, my vote would be 185/190 heads. The smaller heads you have will still make great torque numbers, but will choke off the top end hp somewhat. Could you use them; sure you could. 205/210 is getting a little big, more oriented to high rpm, but it's all in what you want.

mebirkle

thanks... any idea how much i would suffer with my heads on the 331 with only the 170 runner size??

Duncan_GT

Not much. In my opinion that's within a good range. A 190 would be ideal, but if you already have a 170 Eddie head then run it unless you are wanting to get something else. I see the edelbrocks aren't CNC machined. Just remember the heads are where you make your power, so something like a TFS head would probably benefit you a lot more, especially with the new 11R castings

bluebeastsrt

170cc heads are fine.

mebirkle

Sorry... 1 more question.. What hp difference between 170 cc edelbrock and 190 edelbrock or something else? Trying to justify a 500 cost difference after selling my edelbbrocks and buying the new heads.

Duncan_GT

Can't say. You can't look at it by horsepower terms. If you have 170 heads already, run them

reldla1996

The power difference might be 10-20 hp at peak power, but it will also be essentially zero hp difference from idle to 5000 +/- rpm. Makes it hard to justify $500 difference, but it's all in want you want, can afford, and are willing to spend the money on. Before I switched plans and built my current engine, I had planned a 331, and had planned to reuse my existing TF TW 170 heads - similar to what you have. Almost every decision is a compromise about something.

tinman

Just MHO but I'd stay with the heads you have now.
If you were going racing I'd say to use at least a 185cc intake port head......