Inliners International Forums General Discussion Engines proposed engine mods

I am doing a resto–mod on a 53 Chevy 3104 P/U with a ‘56 235 hi-pressure engine and 3 sp. transmission. The truck will be used primarily for vintage touring. The suspension will be restored per 53 standards with the exception of front disc brakes. The open drivetrain (trans., diff. & driveshaft) will be rebuilt and a new ring and pinion set installed in the diff. for street use. The performance options should be those that might have been used in that period for upgrades.
Current plans for the engine include:

HEADS:
Offenhauser dual carb manifold w/ 2 Rochester B 1bbl carbs
Fenton split exhaust headers
New exhaust valves and hardened seats
4 or 5 angle grind on valve seats
Matched ports, intake and exhaust
Cc’ed chambers, matching chamber to gasket and cleaning up any hot spots around the plug threads
Replacing valve train parts for new cam

BLOCK:
Re-use what I can and replace what I can’t
Clean up the cylinders and re-fit rings and pistons as req’d.
Inspect, clean up, shot peen and balance rods
Balance pistons
Mild upgrade on cam, ~260° duration

IGNITION:
Electronic module in stock distributor or stock appearing electronic distributor (no external box)
Stock appearing but higher performance coil

First, I would like your comments on the modifications planned for the truck. My experience is with high revving, small displacement race engines so this truck and touring are new concepts.
*Since increasing compression is cheap horsepower, how high can I reasonably go with regular gas and how is it best to get it? Pistons? Shaving heads or decking the block/or both? I’ll be taking a skin cut on both during the rebuild.
*Any recommendation on the cam? Grind and mfg/supplier?
*Jetting recommendations for the dual Rochester carbs and is dual and Rochester 1 bbl carbs the right answer? Where can I get calibration info on multiple carb set-up?
*Can you recommend a good “How to Rebuild and Modify Your Inline Chevy 6” book for the one (or two) questions??? I may have missed?

And thanks for any help you can supply.

Dear John;

The 'mods' you suggest are strictly for an "high rev" engine & of no value (cruisin) @ 2,000 +/- RPM.

I would build a 'stock' 261" with a large 2bbl.

A stock rear end & a 3 speed with OD (which will 'bolt in') is a better deal too.

All of this is 50s era equipment and will last a long time, "freeing up" your money/time for enjoying the vehicle or racing (your others) etc.

Good luck.

Mr. Schluter,

Many of the modifications that you are considering were tested by Frank McGurk and others back in the 1950s. In the Tech Tips section of this BB is a summary of a series of dyno tests by McGurk on a 261 back in 1955. Even at 2000 rpm the modifications that you are considering raised the torque and horsepower by about 25%. The smaller 235, with about 10% less airflow demand, might not realize as much benefit as would a 261, but I would bet that at least 15 to 20% at around 2000 rpm is possible. I had similar modifications on a 1954 235 back in the late fifties and the benefit was noticeable and enjoyable at normal driving speeds.

As John M pointed out above, a 261 will provide even more enjoyment. As for getting to higher compression ratio, pop-up pistons would be good if you need new pistons.

Frank McGurk, California Bill Fisher, and Roger Huntington published several books (more like pamphlets) back in the fifties. I have seen reprints advertised on Ebay and in Speedway Motors catalog and elsewhere on the internet (e.g., Amazon.com and abe.com). Leo Santucci’s book on the 292 is a great book, but not directly applicable to a 235 or 261. I hope that he includes a chapter on the classic Stovebolt sixes in a future edition.

Links to Road Runner’s post and to California Bill’s book are below.



link to 261 post by Road runner

California Bill\'s Book