The Stovebolt Site Forums The Shop Area Engine Shop A little more oooomph??

I would like to get a little better performance out of my stock 235. What would be the simplest first step to increase performance (horsepower) without doing any radical engine rebuilding? Thanks for any ideas!

Manifold changes. Split exhaust and more intake, either dual carbs or a 4 bbl. Next step is a M4F cam

Thanks for the suggestion Fred, this is along the lines of what I was thinking. Do you have any suggested suppliers for manifolds/carbs etc?
Thanks again!

In my accumulation of vintage Hot Rod mags, there are many articles reporting engine builds where they install various speed equipment and then do dyno tests (just like they still do today). Every one of these old tests done on the 216, 235 and 261 Chevy inline six reports the highest single HP *bolt-on* gain resulted from installing dual carbs (no 4-barrels back then). But...Torque isn't helped much, and the HP gains seem to be in the higher RPM ranges. Next biggest increase comes from bumping up the compression, either by milling the head or pop-up pistons - and that DOES increase torque throughout the RPM range. Some cam grinds show similar improvement but others actually hurt output...dual exhausts (Fenton or split manifold) usually didn't raise the numbers much, but probably helped bump the output with dual carbs. So much for bolt on mods. The most dramatic increase, by far, was by increasing cubic inches. This always resulted in a healthy increase in both torque and HP over the entire powerband. Conclusions? Improving the breathing of a 235 should be addressed first...and start with a 261 if possible.

Intakes are available for either two ones or a single four. Tony has done the four with good results with a 500 edelbrock. On my friend's 261, we had dual Rochester ones, and switched to dual twos. We used the Holley-Weber progressives that Langdon's Stovebolt sales. Had to use adapters, he has them too. The Webers made a huge difference, with a full race came he has his idle set to about 650 rpm. With the progessives he still has good low end torque, and has gone to 6,000 rpm on the top.

Another easy mod is ignition. HEI's from the 250 can easily be machined to fit, but they are starting to get hard to find. If your points distributor isn't worn out, you can drop in a Pertronix for under $100. My local parts store can get one on a day's notice. Also a MSD-6 box will help too.

Sixpack is right, but you are looking for simple and economical bolt-ons. You might start planning for long-term items, too. A 261 with a ported and shaved head, GMC pistons and a balance job in addition to the cam, headers and dual carbs can easily put you in the 200 hp range.

I know this is off topic but what kind of work would it take to put a 292 in the same power (200 hp) range?

Ftyler,

You have to do very few things to get 200 horses on a 292. The basic steps, headders, a li'l more compression, a bigger carb and a better cam. You can have the amount of power You want and still have a very decent, streetable engine. I'd say that You can even expect a li'l more than 200 horses. If I'm not mistaken, Isky offered a cam, hydraulic grind and very streetable(sorry, no numbers, guess it was a 266 supercam). Holley had a carb, 450cfm, mech secondaries, single pumper, good choice, or an edelbrock 500 cfm would also do. Mill at least 040" from the head, and do not forget headders, 1 3/4 primaries should be adequated. Been doing things here in this lay out for a while, pleasant results ever.
Hope it helps.

If you are interested in working up a 292, get the new book out on the late model sixes. Can't recall the name or author, Inliners has an article on it. I bought one from Amazon. And you can approach 300 hp from a 292 for some $$$, 250 hp isn't that difficult. And the parts aren't as expensive, either.