VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 207 Max HP

I'm looking for suggestions and input for an engine I just bought. It's a 1935 207 (casting # 2 5 837591-1) that has been completely disassembled and gone over, Head (#837682) has been redone with what looks to be new valves, springs, guides and is still in the plastic warping. Rods have been re-done with new bearings pored. It is supposed to have a new crank ( most likely refurbished ) and a new cam. Carb, water pump, fuel pump, starter, generator have all been rebuilt. I also have a good full cyl cooling block (#836010). What I would like to do is build one of these engines with the maximum horse power I can. What can I do? I don't want to race it, I just would like to be able to get the most I can and maybe increase the Max RPMs without killing the engine. Also I would like to keep the 207 not replace it. Thanks

I would not do anything major to increase the horse power on a 1935 or 1936 engine.
The 837682 head is a late style 1935 head with the valves with the better late style keepers. The 1936 head would be a slight improvement as it has an "improved" combustion chamber with a higher 6.0 to 1 compression ratio. The 1935 was 5.6. The 1936 had a revvised cam shaft - to produce more power at a lower RPM. Then, to protect the "more powerful" engine the 1936 used the 1935 Standard smaller intake manifold. This was to govern the RPM of the engine and to quote Chevrolet "to govern the high speed"....The higher compression and new combustion chamber added power but the manifold deducted some at higher engine speeds....The 1935 Master has 80 HP and the 1936 had 79.
In other words they wanted the engine to stay in its safe RPM range. In GM provong grounds tests the 1935 and 1936 Masters had about the same top speeed (77 MPH) but the 1936 had faster high gear acceleration in the normal driving speeds.(and better gas milage).
Either of these engines can maintain 60 MPH if they are in good shape.

The full cylinder cooling wouldn't be that necessary. Would rather have a good '35 block than a questionable 1936 block.
The "improved" 1936 head was sold through parts as the replacement for a 1935 after about 1938.
A 1936 oil pump and distributor must be used with the 1936 block - same for the 1935, the 1935 parts should be used.
These engines would benefit from the higher pressure gear type oil pump that was sold for replacement after about 1938. It feeds better volume/pressure to the oil trough pipes.
For sure you do not want to increase the max. engine RPM on this engine. They will rev up to 4000 RPM but not for long. Around 3000 is safe, and safer if it has the lighter aluminum pistons.

Thank you for that information. I had thought about the aluminum pistons. I also thought about a good precision balance of the crank and rods but I still worry about normal road speed driving. Living in PA we a lot of hills to deal with. I have been told that the 207 is not a great choice for a regular driver. I would like to build on 70+ years of engine development to bring an old engine to the best it can be.

When everything is done right a 207 will go many, many miles. You will find that 50 MPH is about all the faster you will want to go in a truck (it will sound like 100 MPH). For the his the 1936 engine produces the most power at normal road speeds. The balancing is an excellant idea.

50 mph would be fine. It's 0 to 50 I'm a little concerned about. I plan on using my truck as much as practical. I have no intentions on driving on the interstate or anything like that. I just to make sure I'm not a hazard when pulling out of an intersection or going up a hill. I don't want to change the looks of the engine with things like intakes or headers or carburetor.

That is the speed range the engine was designed to run in and have the most power. Just set the intake up like a car and not a truck. The truck had less power becuse of the restrictor betweeen the carburetor and intake manifold.
My '34 car, which was a few hundred pounds heaiver could be wound up to 20 MPH in low and 35 in seconed without really screaming the engine and had good power in high gear from there to 60MPH.