Who out there has experience with the aluminum high compression heads that do not require new pistons but rather exchanges neatly with the original head? They typically cost 3-400 dollars. I am wondering if it might be something worthwhile for a car that I like to tour with.
Definitely worth it, and it'll be good with original pistons. Probably adds stress to the engine, but so far both of mine are good.
Daniel -- As far as I know, none of the aftermarket heads requires a change in the stock pistons. They definitely are worthwhile, as Hal said. You'll like it.
While you're at it, you might want to check your rods to be sure they're within spec for tightness. Sometimes, if they're marginal, the additional compression will cause a noticeable knock sound. Or you could put the head on first, then listen to it and adjust the rods if necessary.
Daniel, The following are my observations only and should be taken as such. I replace the "stock" head with Z's on 3 of my T's. No changes in pistons or cam-shafts made. Here is my experience. Was there a noticeable increase in HP? Yes and No. There was an increase but..suttle. The HP increase in and of itself, in my judgement, is questionable if HP increase is what your after. I had problems in stopping head gasket water leaks on all 3 after I made the swap. You need to torque and re-torque the head bolts after installation. I mean multiple times. The major increase in HP came after I installed the Chaffins over sized intake and exhaust manifolds. That made a difference you could write home about. This is my experience only and not to be judge as absolute in any way. Jerry.
Thanks Jerry, I had a 17 earlier with a Z head and it had rod knocks. I am skeptical, but Hal and Mike both seem to think they are worthwhile. Let's see what others might have to say about their experiences with them.
Sorry to go a little OT here,.. but Jerry, when you said you use a Chaffins over-sized exhaust, did you mean a dual exhaust?, that's all that i see them selling. I have the intake, and was just curious. Thanks.
Hi.....Yes, dual exhaust and the enlarged intake manifold. To the dual exhaust I ran dual pipes into a glasspack muffler then into a single enlarged tail pipe. This set up made made a difference in hp that I could fell, right away. This is not to say that the z head did not contribute but the real difference was in the dual exhaust and enlarged intake. That's my story and I'm sticking to it...Jerry
I installed a high compression aluminum head on my '15 12 years ago. Dramatic improvement in torque at all speeds. Best $300 I ever spent. No issues of any kind except a bit harder to crank.
The head I bought was a low head made by Ralph Reeder. Wish I could buy more of them!
I have a high-compression, aluminum head and like Jerry, I'm experiencing some coolant leakage. _When driving, I'm ever mindful that my engine and its Achilles crankshaft is a century old and so, never, ever "floor" the throttle or use anything approaching full power. _And to me, these two things mean I probably should have stuck with my original, iron head.
When I rebuild engines, I always take the block and head to a machine shop and have them milled flat. I have never had a coolant leak. I'm not saying that you should pull your engine and have it milled, Bob, but it's something to keep in mind whenever you have it out of the car.