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Discussion Starter · #1 ·
I may be getting a set of bare '65 289 heads for free soon, and I have a few questions. My car has a '68 289, so I'm considering the other heads since they're free, and they won't have the Thermactor bumps in the exhaust port to deal with when I port them. Also, they have the more common 54.5 cc combustion chamber.

I plan on having them totally gone through, and would like to go to bigger valves. What's easier/cheaper, the 351 size (1.84/1.54), or the Chevy size (1.94/1.60)? Also, what about rockers? I'd like to go to either stamped roller rockers, or aluminum rollers, but I'm not sure what's available when it comes to the rail style rockers. Any help would be greatly appreciated.

-Brian
 
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Discussion Starter · #2 ·
If your having the seats recut for bigger valves, might as well go as big as possible. Minimal, if any difference in cost. While you're at it, look into threading the heads for studs and get away from the rail rockers. Remember to use guideplates and hardened pushrods. Also, use roller fulcrums - that's where the horsepower gains are made with roller rockers.
 
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Discussion Starter · #3 ·
What all is entailed in getting rid of the rail style rockers? Is it just a matter of guideplates and hardened pushrods? I was thinking about screw-in studs, but I'm not sure it's necessary for my use - is this something I could do myself? Finally, for the Chevy valves - does the stock Chevy length work as long as you're not using rail rockers. IIRC, the special length is only for rail rockers, and stok works for non-rail, but I'm not sure...

-Brian
 

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There's about 100 people on this forum more qualified to answer your question than me, but as they haven't responed yet, let me try to muddy the water a little.

I don't think '65 heads have rail style rockers. I think they have pressed in studs (except for hypo heads which had screw in studs). I THINK all you have to do is have a machine shop press out the old studs and drill and tap for regular screw in studs. Hopefully someone will post that has done this. I thought about it, did a little research and then opted for aftermarket heads instead. I'm not saying what you're doing doesn't make a lot of sense though. You'll spend less $ and should get a pretty decent boost on performance especially if these heads increase your compression ratio.

Phil


'65 Convertible (with many mods.)
http://www.blueriver.net/~finite/Pony.htm
 

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1971 Mustang Mach 1, 351c, Ram Air, Auto, 3.50 Trac-Loc, PS, PB, A/C
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As for the valve sizes, I know when I worked at PAW years ago, they would put used 1.94 and 1.600 chevy valves in 289 headwhose seats were pounded out. they'ed install seats in otherwise unuseabe heads, but didn't relieve the chamber around the valves, which only actually let half of the valves diameter breath, so improved power was minor. The 1.94 intake also hangs out into the spark plug recess....not too kosher. Better would be to install the 1.88 intake Shelby American used with the 1.600 exhausts and have the shop relieve the chamber for those
 

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Old threads are fun aren't they? Right or wrong, on a set of 65 heads I used 351 windsor valves, hardened exhaust seats, milled the stud bosses down and added screw in studs and vitron seals..all new guides.., kept the stock rocker arms but added chevy fulcrums with oiling grooves..dual spring valve springs that came with the comp cam kit...and of course ported the intake and exhaust runners-may run my old hi-po manifolds also port matching them to these heads...Almost as much as new aluminum heads but way more fun revamping them for my wifes all stock 65 still under restoration!
 

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@HoosierBuddy , the “rail” rockers refer to the rocker tips that have little rails to maintain alignment on the valve tip. This eliminates the need for pushrod guide plates.

as many have said, probably more cost effective to go with aftermark heads, but for many us, we like to mod the old school way for one reason or another.

for my 68 J code 302.. I began with heads that already had a mild port job done. I had the Chevy 1.92/1.60 valves w hardened seats installed. I machined the bosses down for screw in studs and guide plates as well. Hardened pushrods, comp cams SS rockers, and a Crower 15321 Solid lifter cam.

No doubt, there are cheaper ways to make power, ...I just wanted to build an old school, solid cam SBF for my mustang. Since I will never find an affordable GT350.. at least I can simulate the experience to some degree. 😁
 

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@HoosierBuddy , the “rail” rockers refer to the rocker tips that have little rails to maintain alignment on the valve tip. This eliminates the need for pushrod guide plates.

as many have said, probably more cost effective to go with aftermark heads, but for many us, we like to mod the old school way for one reason or another.

for my 68 J code 302.. I began with heads that already had a mild port job done. I had the Chevy 1.92/1.60 valves w hardened seats installed. I machined the bosses down for screw in studs and guide plates as well. Hardened pushrods, comp cams SS rockers, and a Crower 15321 Solid lifter cam.

No doubt, there are cheaper ways to make power, ...I just wanted to build an old school, solid cam SBF for my mustang. Since I will never find an affordable GT350.. at least I can simulate the experience to some degree. 😁
Yes. I learned that in the 20 years between when I answered this post and when you corrected me.
 

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Speaking of right or wrong, contrary to what was suggested above twenty years ago, there are no "horsepower gains" from roller rockers. You can actually lose horsepower running cheap roller rockers since they tend to flex a lot.
If someone just slaps them on then yes I agree that they would do very little, but set them up correctly with a narrow valve tip sweep (along the lines of the ubiquitous mid-lift rule) and use them with stiffer valve springs and you could a little bit more than very little...:cool:
 
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