G horsepower gain

[1949ABG]

I'm getting ready to do a complete engine overhaul on my '49 G.

How much actual horsepower would I gain using new aluminum high compression pistons vs. just putting in new rings on the old ones.(Assuming they're usable.)

I'm planning on putting on a gas manifold. I'm also wondering is there a HP difference between a mag and a Delco distributor?

Thanks for your input and advice!

 

[1949ABG]

Should have stated that all engine components are going to the machine shop before re-assembly.
 

[jd50A]

For what its worth--- I had my 1950 "A" done.
Bored .125 over stock, milled head by .20, High compression alum. pistons. Compression is 130 psi, dynoed at 47 hp with 93 octane gas. It starts and runs well, no problems, that was 3 years ago. I have heard a cam will up the HP without much else done. Have no experience with that. Put a post on the Pulling forum. They should be able to answer all questions.
 

[JLG]

M&W pistons and LP manifold (I think that's the only gas manifold you can get new) brought my G up to 55hp. I was very happy. Switching from a mag to a distributor won't gain you any power, but you can convert the distributor over to electronic ignition. The old points work fine, but the electronic ignition is maintance free. I did it 5 years ago and haven't had to touch the distributor since. I've since put in a reground camshaft, that got me to 58hp.

That's a nice looking G! Wish mine looked that nice.
 

[bigboreG]

I overhauled my 52 G with .090 over hi compress alum pistons , gas manifold, and electronic ignition. Also reground cam, just a stock grind. It easily pulled 50 hp on a dyno with digital readout. It does not have a flathead. Burns alot more gas, but is fun to work so I dont mind. A model G is capable of attaining considerable hp gains with only slight mods, the cubic inches are there its just a matter of utilizing them.
 

[cushman]

When I restored my "47 G I installed .090 aluminum pistons and a gas manifold and it makes 54 horspower.It made 40 with the cast pistons.
 

[buickanddeere]

As previously stated. The cam and followers will be worn from 64yrs of service. May as well talk to a cam grinder about what compression ratio to make the pistons.
The cam and compression ratio have to match rpms and octane of fuel to be used.
Gas manifold, five angle valve job, blend the rough edges out of the ports. Dry air cleaner element conversion.
A distributer will allow spark timing to vary and follow rpm. Won't tend to kick back when lugged to low rpms.
 

[bigboreG]

The cam is the first place to start in an engine. Then the crank, and lastly the compression. The engine needs to breathe, and to be able to utilize the raised compression, the valve train and all of its components need to be in top condition. If your not building a puller, then stroke wont matter much, leave the crank at stock specs. Your machinest will make sure the crank journals are true and up to specs. As B&D stated, a five angle valve job will make a difference, as well as a port and polish. But you know how much you can spend, so if your budget is tight, your money spent at a good machine shop will be well worth it.
 

[Sadowsky]

We did a style G with .125 over gas pistons, milled the head down to the eyebrow, cold manifold, and big nut carb and it made 62 horsepower on the dyno. That is an easy build that makes a great boost in power.
 

[russn]

Have any of you tried the high ratio rockers from Murphys? I thought about trying them on my 48A.