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Discussion Starter · #1 ·
Ok Ive posted on here a few times, I found a set of 3872702 heads I believe 65-66 date heads, Im told they are a 98cc head,

My short block is built and in the car, It is a 454 .30 Over TRW L2399 pistons (.95) Dome,Rpm Performer Intake, My block has never been milled. My Cam is a Comp Cam 292H .550 lift 292 duration.

1)Can I use the 3872702 heads?

2) Am I going to have enough clearance with the 3872702 heads because of the 292 Cam and dome pistons?

3) What would my compression be if I used the 3872702 heads?

4) How much HP would the engine be making, Im hoping for at least 400 which really shouldnt be hard with a 454.

Thanks for the help :D
 

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First. The early heads are not compatible with modern fuel... Use hard to find N series plugs. Then you must check the dome for contact with the edge of the head at the exhaust side. Just install the head with no gasket and turn engine one revolution. check for contact. The head will rise or leave a mark on the piston. If they clear with no gasket you are OK. If they don't, plan on dome mods.

Compression will be close to 11-1 (depending on head gaskets) not good for todays gas.
 

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Discussion Starter · #3 ·
The 3872702 heads im buying are $750. Id really like to know If i can use them before I fork out that kinda money.

I have a .550 Lift, 3872702 98 CC heads, and L2399 .095 Dome pistons. Am i going to have any clearance problems? has anyone had a set up like this?
 

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OK this Keith black site has a lot of really good information
http://kb-silvolite.com/calc.php?action=comp

I didn't check the piston number but if you clear the heads you will have lot's of compression. I would think the ports are a little small for the compression and camshaft you list. I mean these heads will give you just guessing 11/1 but those are 396 heads? Midrange torque would be freaking amazing but I am guessing you would be limited at the upper RPM.
You can clearance to make fit, you will make more than 400 HP, It will burn the tires off. ... I would want larger ports but all things considerd It should be a blast.
 

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Discussion Starter · #5 ·
Would I be better off with a set of 063 Closed Chamber Heads? They are 101cc Im not so much worried about the compression as long as its under 11-1. the 702 heads are completely rebuilt harden seats, 3 angle valve job etc.

What would you guys do? 063's or 702's What is a better casting?
 

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I looked up the pistons and they are open chamber pistons, like Bobcrman posted check and make sure they fit first. can you borrow one? see how much grinding would be required if possible? Or draw the chamber on some paper, I havn't seen pics of the piston dome but you might be out of luck using a closed chamber head if the dome continues over to flat head surface oposite the spark plug? I have a set of closed chamber pistons I'm going to use on an open chamber head! as far as ports between 702's and 063's I don't know if they are any different? Combustion chamber size wouldn't make much diference. I have a set of 063's on my 489 and they work pretty nice!

http://www.flatlanderracing.com/trwchevy454.html
 

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Discussion Starter · #7 ·
It is a very Small dome .095 I had a set of 049 heads on the motor When I bought it when I freshened it up and CC'd the heads and they were 122cc heads, - Im told it will be like a 8-1 motor with open chamber heads and the .095 pistons,

Also I have TRW L2399 030 Pistons, They are a direct replacement for 1971 LS-6 motors and I read in a few places they are closed chamber Heads, I will post some pictures tonight for you guys,

Also, They guy with the 720 Heads said the springs were only good up to 5500 rpms, My cam range is 2500-6500Rpms. Would you replace the vavle springs or just settle with the 5500 springs. The heads are ready to bolt on, The motor is a 1970 Chevelle th350 tranny built, shift kit boxed control arms etc. its going to be a street car that I may take to the track every once and a while. 5500 isnt bad for the street but it would be nice to have that extra 1000 rpms
 

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That TRW link I posted lists your piston as a LS6 Open chamber piston, yup, that doesnt make any sence? Sounds like the same pistons I have with a little smaller dome. still check to make sure nothing hits! Valves too!
Lists it at 10.2/1 on the link.
I would go with springs sugested by Cam manufacturer. Make sure the retainers arn't going to hit the guides with .650 lift.
Measure your deck clearancxe. I like a tight quench so if you end up with .040 piston to head clearance that's great. Might need a steel shim head gasket if block hasn't been decked but tighter the quench the less chance of detonation. My flat tops stick out of the block .006 and I ended up with .028 piston to head clearance. A little tight for a car however.
 
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