3872702....65-66...oval..CLOSED..396, 427, 98cc chamber

I found a set of these heads to go on my 462 that should give me a static compression ratio of about 10.25 to 1.

1st question is will these heads flow well enough to make 500+ HP?

2nd question is what head work should I consider, besides 2.19 and 1.88 valves, to meet my 500+ HP goals?

I have to use a head with this, or similar size combustion chamber to get the desired compression ratio. Are these heads worth putting money into?

Thank you.

In a word, yes if you do them up like you mentioned!!

pdq67

Those heads will flow enough to support 550+ streetable HP with those cubes and compression ratio if you add the large valves and unshroud the intake valve and have the right cam. The unshrouding will increase the chamber by 2-3 cc's so milling of the heads may be needed to maintain your desired compression ratio.
Make sure the valve pockets are nicely blended into the new valve size. Intake matching and valve guide smoothing will help also.

Those are the early head with the bad chamber. The big valves don't really fit and you can get into water if you try to open them up to the 215 specs. I have used them on 396s but I wouldn't recommend them for a bigger motor.

interesting.... anybody else have any negatives?

I'd swap them to someone that needs them for a restoration and get a set of 215/290/063 heads..........

I think you have a FINE plan, Brit! Did you ever get solid info on your pistons?

Are those the 'bathtub' heads? If so, sweep the chambers around the intake valve for sure, {not sure about the exhaust}, because the valves are shrouded. Otherwise, don't go nuts. Below the valve seat, clean it up, short sides if you know how, and you will support a lot of ponies. If you are going to spend major bucks, I dunno, I wouldn't. I got a set on my 468 {#390's}, and the semi open's look a lot better.

I'm running 206's on my 496. They have a 97cc chamber. I believe they are a 66-67 head. I run 2.19/1.88 valves, had the bowls cleaned up, gasket matched intake to head, and unshrouded both valves. They work great. Don't have any power numbers though. The thing I like about the small chambers is you can run basically a flat top piston and get good compression. I run a 5cc dome on mine and have around 11:1. Hope that helps.

Matt

Thanks everyone, I'm not in a huge rush and I've got a lead on several castings so I'm going to keep researching and try to make the best decision.

Jimmy, someone on the board was able to give me some good info on the pistons and confirmed that I need around a 100cc to get 10/1 compression.

i'm using the same heads on my +.060 396, stock valve sizes. not bathtub chambers, but small enough to need chamber work to fit the larger valves. with my small bore it's not worth it due to shrouding, but i'm figuring on them motivating my Nova to mid 11s or better next year. with large dome pistons (mine are 30cc) the chambers will require some massaging.

Originally posted by Mike Feudo:
Those are the early head with the bad chamber. The big valves don't really fit and you can get into water if you try to open them up to the 215 specs. I have used them on 396s but I wouldn't recommend them for a bigger motor. Mike,
I was under the impression that the 7 closed chamber, oval port heads were just about identical internally, except for the minor changes in combustion chamber CC's. I thought the difference between the (702,390,802)advertized 98.427cc chamber and the (215,063,290)advertized 100.967 cc was just around the spark plug area.

When you say opening them up to 215 spec's are you saying the later heads actually have a larger bath tub design, that unschrouded the valves more?

I am confused on this manner. :( Any help would be appreciated.

PS I know I left out the first 206 head at 97.167 CC's.
Bill

I have seen large valves installed and unshroudind done in the 702's and then flowed. They flowed near identical to my 215's. The chambers are very similar except the 215's are more laid back around the plug near the surface of the head.

I have 063's That we put 2.19" intake and left the 1.72" exhaust as is. Leaving the exhaust at 1.72" creates better flow and avoids alot of the shrouding problems.

Regards,

Originally posted by JRA:
The chambers are very similar except the 215's are more laid back around the plug near the surface of the head. This was my understanding also. I had the larger valves put in my 702 along with the unshrouding and bowl work and they came out great.

I would still like to know for sure if the only real difference between these heads is anything more than the above mentioned spark plug area.

Are the ports the same? I have assumed they are.

Bill

ttt

Anyone? :confused: I am interested if anyone knows for sure the internal differences of these cc oval port heads. So many times the 215 head is referred to as the good one, when I believe they are the same, except for the external changes of temp sensor bosses, or sparkplug seat, or spark plug shield bosses and the above mentioned spark plug combustion area relief area. ???

I can see where there may have been some different core changes which would account for some concern when enlarging seats or unschrouding valves, but is there any difference in combustion chamber or port configuration that would make one of the 7 heads more desirable?

Bill