Low vs. Medium vs. High Rise Heads

[fastback427]

Hello everyone,

I am looking for a good set of heads for my 427 side oiler. I would like to keep a ford 427 head on it, just for the history of the engine parts etc.

So tell me this, what the difference between the low, medium, and high rise heads in a nutshell? I know intake and exhaust ports etc were different, but which ones are the best.

My engine is going to be a street engine 500-600HP, and also are the high rise heads taller than say the low rise heads, because I need all the hood clearance i can get.

Any Help and info is greatly appreciated,

Thanks,
Matt

[AUME2010]

The best resource for this is Barry's book on High Performance FE's (How to Build Max Performance FE Engines). It gives a good explanation on the differences. The most noticeable difference that i can recall is the rocker arm mounting pads are different and the angle of the valve cover etc are different on a high riser.

[PGreenSVT]

I would think for a street engine the medium rise heads are going to give you the best balance of power. The hi rise heads need rpm and are top end heads at the expense of bottom end. I equate the low rise heads with stationary and marine work.

[Glenn N]

LR and MR heads are both the same height. Just different chamber and port sizes. MR heads have a much larger combustion chamber. 92cc's as cast vs 74-76 cc's on the LR's. The Highriser heads are indeed taller and require the matching intake. Robert Pond sells a NHRA legal version of the MR heads in aluminum. Much more potential than the stock iron MR heads. www.robertpondmotorsports.com You can always paint them blue?? Tunnelport heads are another option and will fit under the hood. Same installed height as the LR-MR heads. Harder to find in nice shape and have the same combustion chambers are the MR. I've seen a few nice sets of OEM iron MR heads lately. They can get pricey as the TP and HR stuff is too. But they are still out there. The bad economy has flushed out a ton of parts over the last few years that normally stay stashed away. So it's a pretty good time to buy although the prices on the more exotic stuff is still pretty high. Another thing to keep in mind is if your 427 already is a built shortblock. As piston choice will reflect somewhat on the heads you buy.

[fastback427]

Thanks,

I picked up a nice set of tunnel port heads and a TP intake so i am going to run them. Hopefully they will give me a good range of power for the top and bottom end.

[toolerwayne]

Nice. Should be a screamer. You may have hood clearance problems though. Mine just makes it and could use more air cleaner. If I had it I would run it.
Wayne