The Stovebolt Site Forums The Shop Area The HiPo Shop 235 engine rebuild

Hello, I'm another new guy to the forum, haven't posted my pics yet but I will. I want to start my engine build for my 1950 1/2 ton. I'm using a 54 235 out of a "big bolt" my brother had. I already found a T5 from an S10 for a transmission.

I'm building a rat rod and want to hop up the 235 a little bit. Planning on getting a dual 1 barrel intake and fenton headers. I havent found any answers by searching or in the tech tips so if these questions have already been answered I apologize.

Does anyone make domed 9, 9.5 to one pistons? Or do I have to go custom? I know that I can mill the head down but from what I read it doesn't bring it up to 9.

And what sizes valves should I look for? I read an artical from another post were they ported the intake side of the head to 1.625 on the bowl, and 1.5 on the runner. I was planning on goin that route.

I'm sure I'll have more questions later but this is were I'm at know. If anyone has any experiance or sources for parts I would apriciate it. thanks

Dreasoner,

Sounds like an interesting project.

Have you read the Racer Brown article in the May 1955 HRM about Frank McGurk's work on a 261? Most of the modifications and results would also apply to a 235, if adjusted for the displacement difference. I've followed this article for the 235 and 261s that I've built over the last fifty years.

Pop-up pistons were used to get the compression ratio up into the nines. I'm not sure if anyone stocks them anymore. You could check with Ross or Arias. Check the "12Port Adverisers" link on the Inliners' site.

Have you checked out the Webrodder Series on the 235? it is a little different approach than what you may be contemplating, but lots of useful and interesting information.

Hoyt

When you over bore, you raise the compression. I believe on the 235, I know this is the case with the 216, when you mill the head, you need to set the valve seats in. Back in what I call the good old days, guys would fill in the combustion chamber a little with weld, to raise the compression. This, and a 3/4 cam, is alotta work (money) for little more bang. Plus, sticking a lumpy cam in there is going to drop your torque, so if you wanna go on the street and strip, you'll want a 4.11 rear end, with a stock tranny. I don't know about t-5's. Once you put the headers and lake pipes on, it doesn't matter how fast, or how much power you've got. It'll sound like you're racin on a dry lake. Its a very distinct sound.

i don't have an answer to your question (kept my 235 stock) but this guy answered one of mine and here's a video of his insane 235....http://rides.webshots.com/video/3062003080092261295PwyXcS

he's user name LONGBOX55

hope this helps.

Flat tops are the only pistons currently made for the 235. Given the odd shape of the combustion chamber, especially compared to the cylinder bore, a popup piston would be somewhat dificult to make and to get decent results out of. Milling the head and an overbore are about the only realistic ways to get the compression up without swapping to Fisher or Wayne head.
Any reason you want the compression at 9:1? I'm only maybe runngin 8.35-8.5:1, and have plenty of power for the street. Plus it runs great on cheap gas.
For parts, check out Patricks and Langdons. I used Patricks myself, very helpfull if you have problems.

Me again.....so you're planning your engine rebuild. Good news....but there's something you need to consider before you throw a bunch of money into your 235. First of all, it's a 4 main bearing engine that was configured to make low-end torque and last a long time. Granted, you can boost up the compression, do some some head work, add a rumpy cam, multi-carbs, HEI, headers......and it will still be a 4 main engine that doesn't make much more horsepower, a tad more torque, and will not give you the bang-for-the-buck you're expecting.

However, if you plan to build a great cruiser....the 235 is a great candidate. With your T5, a decent R&P ratio and some sensible upgrades it'll be a hoot to cruise and will turn heads when that 6 cylinder sound announces itself.

This may not be what you want to hear but it's a fact!! If you captialize on the low-end torque, clean up the bore, add a 261 grind (torque) cam and get your gearing dialed in you'll be a much happier camper. When you calculate your horsepower to weight ratio.....even with some radical engine upgrades, you'll see that there is no substitute for cubic inches and a more aerodynamic platform.

Dave

My Bud built This one for his 65 and Man... It really turned out sweet ! and you should hear it WOW !

Thanks for all the input. I'll have to read the other articals. I guess I chose 9:1 because its what I'm use to running on a stock motor. I didn't think about it only being a 4 bolt main. I'll have to check with Ross and Aries for the pistons but I don't want to go custom, $1000 the last time I checked.

If I mill the head don't I have to drop the valve seats, shim the springs and the rocker shaft? I might gain a little CR that way but I don't want to go to far. I think 8.5:1 would be good enough if it just took a set of flat tops.

I guess I should say that I don't expect this to be a racer just a fast crusier. Something different from my other projects. I'm putting a 455 in my 68 cutlass so If I want to race I'll get my fix there.

What about headwork? Any porting that you guys have done? anyone running larger valves? Are the ports matched to stock on the aftermarket dual intakes? Or do they have larger ports? I was thinking about the dual intake from Particks.

I have not ported my truck. The Offy intakes have the same port as stock. Having a 235, you can get a repop Offy, or Fenton intake. Or, using ebay and patience, you can get an Edmunds, or something else. A book to get, that you'll enjoy is the reprint of California Bill's speed manual. Jim Carter's sells it. The book is generally about the 216, but the same info holds true for the 235. There is a section on the 235. He has all kinds of info on porting, and substituting valves, etc. As said, the greatest thing about the six is the low end torque. I'm in fourth before 20 mph when cruising, and can go straight to WOT from there. When you are ready to buy stuff, check around from all the vendors, Patricks, Jim Carters, Chevs of the Forties, Langdons and others. There are sometimes big shipping and price differences, though I imagine they get the stuff from the same place. Gotta shop around. There are some cool engine items on ebay from time to time. Some nos, which amazes me, that there are still unopened boxes out there. I wouldn't get hung up on a particular compression ratio. The 216 was 6.5 to 1 stock, and it seems to me if bored out .60 thousands, it goes up to something around 7.5 or 7.25. I would think that your 235 would be similar. If you stick a big cam in there, you'll loose some low end torque. And have to set your idle up to 650 or 700 rpm. If you leave the cam alone, you can still idle at 450. I like that, you can hear each push rod tick, and the fan belt goes so slow that you can read the label on the way by.
That's my two cents. You'll love California Bill.

http://i221.photobucket.com/albums/dd45/HomeCrafter/IMG00178.jpg

http://i221.photobucket.com/albums/dd45/HomeCrafter/IMG00176.jpg

Best bet for pistons is TRW, they're about the only company that still lists forged pistons (just like OE) for the 235. As far as milling the head, you shouldn't have to do anything with the rockers, valve seats, or spring seats. The combustion chamber is pretty big on the 235, and the exhaust valce not only sits rather high up in the chamber, but is also canted as bit.
Not much to be gained by porting, either. The intake ports are already matched up, by virtue of the alignment rings. One thing to watch for, make sure you use a 235 intake. The 216 uses smaller port rings, and will be difficult to get proper alignment and sealing.