GT40P heads on a flat tappet engine

[crimsonclint]

I have a 289 that I'm putting these on and I imagine a few people have these on their classic builds I just don't want to go roller yet. So my question is anyone know a good stud mount style of rocker that would be good for this head. The heads are bare so any suggestions for springs and valves would be appreciated too! The cam is the comp xe262h let me know if ya'll need any more info about the build!! I really appreciate any help...

Btw this is my first post...

 

[D.Hearne]

GT40P heads use pedestal rockers, not stud mount. You'll also loose compression with the larger chambers (60cc vs the 289's 54 ccs) Lookin at about a half point drop in the ratio, unless you mill the heads.

 

[crimsonclint]

Since the heads are bare my machine shop guy is gonna install the stuff for stud mount style rockers. I'm just not sure what size I need, also according to the machine shop since I'm replacing the crank and rods with 302 stuff it will make up *some* compression. I've been looking at comp high energy 3/8 stud 1.6 ratio rockers. ????

 

[bryanvw61]

I got the comp roller rockers (1431-16) and studs (4504-16), they came with a good reccomendation (http://www.stangpro.com/html/articles/gt40p_files/gt40p1.htm), you just need to get the pushrod length correct. Supposedly (7831-16) are close, I got the ones with the rocker arm kit which I belive to be the same. I'll know for sure when I instal them tomorrow night.

Contact me if you need valve springs. I have a complete set of brand new stock GT40P ones that are supposed to be good for .5" of lift. I went with an xe268h cam so I had to replace them with some TFS sprigns.

That link has more great info for a 302 flat tappet swap.

Only tricky part will be the headers, which is not as tricky as people make it seem.

 

[crimsonclint]

Thanks for the info bryanvw61...pm sent

 

[bryanvw61]

pm back at you

 

[D.Hearne]

Since the heads are bare my machine shop guy is gonna install the stuff for stud mount style rockers. I'm just not sure what size I need, also according to the machine shop since I'm replacing the crank and rods with 302 stuff it will make up *some* compression. I've been looking at comp high energy 3/8 stud 1.6 ratio rockers. ????

If you're starting from scratch, might as well go to 7/16" studs and rockers of your choice. 1.6's or 1.7's will work, depending on your cam choice and spring bind specs. 7/16" studs cost the same as 3/8" but are stronger. Won't affect rocker prices either, unless you're shopping the extremely low buck selections.

 

[bryanvw61]

I got the comp roller rockers (1431-16) and studs (4504-16), they came with a good reccomendation (http://www.stangpro.com/html/articles/gt40p_files/gt40p1.htm), you just need to get the pushrod length correct. Supposedly (7831-16) are close, I got the ones with the rocker arm kit which I belive to be the same. I'll know for sure when I instal them tomorrow night.

For all those following this post, this valve train combo went together flawlessly last night. Too bad, I'm still a little ways away from cranking it over.

 

[crimsonclint]

For all those following this post, this valve train combo went together flawlessly last night. Too bad, I'm still a little ways away from cranking it over.

Good I believe I am going to mimic your set up

Ok a bit of an addition to this situation. My '67 will be utilizing this setup, I am curious how much pain it will be to finish out the exhaust after the MAC direct fits(front runner for headers as of post) on a classic. Any x-pipe ideas????

 

[crimsonclint]

Good I believe I am going to mimic your set up

Ok a bit of an addition to this situation. My '67 will be utilizing this setup, I am curious how much pain it will be to finish out the exhaust after the MAC direct fits(front runner for headers as of post) on a classic. Any x-pipe ideas????

Or off road h-pipe?????