I've got a nice Sherman head. How hard would it be on a stock model T engine with a stromberg OF? Is it just asking for trouble?
I'd worry about the stock crankshaft if it's a high compression head.
You can cc the head to calculate the compression ratio to be sure, but I doubt if it would be much over 6:1. That shouldn't hurt your crankshaft unless it is already compromised somehow. It will give you a bump in performance. I'm sure there are guys running higher ratios than that with a stock crank.
(Message edited by Tt bud on April 27, 2017)
Supposedly it's an 8:1 head. I have two motors, one has a 24-27 crank, would that be a better option?
We ran a Sherman Super Fire on our speedster with a T crank, splash oiling and a Winfield model S carb. The engine ran great with that combination. It had great power in the hills and rev'd very freely. My grandfather did remove the magnets and mag coils from the flywheel.
If the bottom end is good shape and well built, I think you will be okay.
Sweet!! I figure if it's going to break, it's going to break anyways.
The '24-'27 axle is stronger.
I think how you use the new power means a lot for how long it'll hold up. Keep it at the rpms where it purrs
I have three Model T's with Prus 8:1 heads. The 1917 T has about 4000 miles on it with no problems. It has 250 cam and runs 54 MPH at top end. The other T has 280 cam and scat crank and runs 57 MPH.
The top end is not the speed I normally run. The best part is the torque at bottom end.
So far I see all pluses and no negatives.
So if I don't abuse the motor I should be fine? I think I will double head gasket it to tone it down.
Philip: The Prus 8:1 claim is just an advertising slogan, in reality they are 5:1 like the Z head. (But still a very good head for a touring T, better quality and slightly more power than the Z.)
Daniel: Double head gaskets sounds good. That'll add about 0.8 cui to the combustion chamber volume (about 8.2 cui in the Sherman compared to about 12.8 in the Prus and Z and about 17.9 in a stock high head) This will lower the compression to about 7.2:1 and hopefully not completely destroy the squish effect that concentrates the combustion around the spark plug and valves.
(Compromises, always compromises with available parts)