Jump to content
HybridZ

gt40 heads on nonroller block


snork

Recommended Posts

stupid question. the gt40 heads wont work on a non roller block, will they? Im just tryin to figure out a way to raise the compression on my late '70's 302 with out doing any machining. I think it would be pointless to do that on a non roller block. Any suggestions?

Link to comment
Share on other sites

I bought some GT-40 heads for my father-in-law's 1968 302 that we put in his 1964 comet convertible. The heads were a straight bolt on.

 

The later model heads utilize a pedestal mount rocker arm, while the older heads use the rail type rocker arms. The newer rocker arm design is much better, but you need to be particlular about which push rods you use. For his application (hydraulic flat tappet cam) we ended up using push rods for a 1982 Mustang. The 1982 Mustang had a hydraulic flat tappet cam and the new style rocker arms.

 

If you are going to use aftermarket rocker arms, then ignore the above, but be sure to get the proper length push rods.

Link to comment
Share on other sites

After doing about two minutes of web research, I came up with the following:

 

The GT40 heads have a nominal combustion chamber size of 64cc and the early 302 have a nominal combustion chamber size of 58.2 cc. So the downside would be that you would lose compression ratio. The upside is that you would get bigger valves and better flowing ports.

 

Why not go to an aftermarket aluminum head? They are available with small (58cc) combustion chambers and even better flow rates.

 

Currently, I am using the Edelbrock P/N 60379 aluminum heads on mine. They are great heads for a stock bottom end. They were worth 10 mph in the quarter mile over the stock heads.

 

Recently, I upgraded my bottom end to a stroker, so I plan to remove the Edelbrock heads sometime in the future and go with either an AFR185 or the new Ford Z302 head.

Link to comment
Share on other sites

Another option is an aluminum GT40 head, they are a little over $900 bucks at summit. Considering it would cost 300-500 for a set of iron GT40 heads I think thats a good way to go.

 

They are available in either 64cc or 58cc so you can still have the better compression ratio....

 

64cc

http://www.summitracing.com/parts/FMS-M-6049-X306/

 

58cc

http://www.summitracing.com/parts/FMS-M-6049-X307/

 

They wont make as much HP as a set of AFR 165's but they are almost 500 bucks cheaper too

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...