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performance parts for Chevy straight six?

60K views 6 replies 7 participants last post by  batman09 
#1 ·
I am building a traditional '54 Chevy custom and rather than go the small block Chevy route, I am interested in building up the original straight six in the car as a builder might have done in the 50's.

Does anyone know how early builders would have souped up a straight six? Are there performance parts still available? What kind of power could I expect as a result?
 
#2 ·
rlackey said:
I am building a traditional '54 Chevy custom and rather than go the small block Chevy route, I am interested in building up the original straight six in the car as a builder might have done in the 50's.

Does anyone know how early builders would have souped up a straight six? Are there performance parts still available? What kind of power could I expect as a result?
I never built one, but a few of my buddies in the 50's did. The "ideal" setup was to get a GMC engine (270 I believe). The heads were milled for higher compression, a split manifold (exhaust) was either fabricated or purchased. A dual carb intake (sometimes three) was substituted. Mallory Magspark (no longer available) dual points were used. Cams were either "custom" ground or purchased.

If you can find the specs on the '53/'54 Corvette engine, that would be an excellent guideline.

Those inline 6 engines would rev up very high and would run well. About the only thing that I never liked about them was the terrible sound they made when fitted with either glasspak or steelpak mufflers.

There are still a few aftermarket suppliers of speed parts.
 
#5 ·
Go with a turbo and make some real serious power and be quiet too. I have seen chevy 292 I6's making 600hp with a turbo!

The cool thing about a turbo is, the stock cam works just fine and the turbo makes the exhaust very quiet. Besides doubling the HP and torque at 15 psi of boost.

FYI, a stock 1964 292 I6 made more HP than a stock 283 of the same year.

I did a turbo conversion on a I6 import and the torque is crazy. 275hp and 300 ft lb of torque at the wheels using the stock cam, 15 psi of boost, and only 168 cid!

Just something to consider.
 
#6 · (Edited)
The old 235 series engine is great rodding material. I hot rodded the one in my '53 Chevy pickup and added a 200R4 OD tranny to boot.

There are a few things you need to know before you start though. Stay away from any 235 or 216 made prior to 1954. They had low pressure oil to the main bearings but used splashers on the rod to dip oil out of the pan to oil them. A standard swap for earlier Chevies was to put in a later model 235. My '53 had one in it when I bought it in '93.

Chvevy made two sizes of this series, the good old 235 and a 261 which went into bigger trucks. Either make great rod material. 235s did not come with an oil filter although you could buy a bypass oil filter as an option. Incidentally, early Chevy V8s didn't come with an oil filter either! Many 261s did come with full flow oil filters. Either way, it is a very simple matter to convert the engines to use a full flow oil filter.

Another option is to swap in a GMC engine. They came in 228-248-270-302 sizes and are virtually the same outside as the Chevy. You need a few Chevy doo-dads to complete the swap but no big deal.

Clifford and Stovebolt, linked to above, have lots of hot rod parts. A hot cam and 1/10" head mill is the first step and gets you a more compact combustion chamber and ~9:1 comp ratio.

An Offenhauser or Clifford intake manifold w/ small 4-bbl or multi carb is next, along with Fenton cast iron or custom split headers.


Electronic ignition is available or easily converted to (see the way I did it in my Journal) and is a good performance upgrade.

Stovebolt has a GMC roots supercharger setup.

Lots of pretty stuff is available;
 
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