Is it possible to bore my '56 Olds block for a 371 4" piston? or should I just stick with a max .060 over bore of the stock? What can the Olds block 324 take and what will I have to do to the heads? etc. any advise would be apprecaited. Thanks-
An 1/8th over should be fine but i wouldnt go much more. check as many places on the water jacket as poss. if you can get feeler guages between the cylinders in the water jackets anywhere through the freeze plug holes take a reading. then from the deck measure the distance between of the same two cylinders. subtract your feeler guage distance from that then divide by two, this will be your wall thickness. then however much bigger on the bore ya want to go divide that by two,that will be how much will come off the wall. As long as you have a min. of .100" wall left your good to go.
Just a caution. What used to work for over bore "back in the day" may not be wise today due to the effect of pitting from the water jacket side over the years. I wanted to go 1/8" over on my 303 and use the 324 pistons but the machine shop, had alot of Olds experience, recommended nothing over .060.
talk to almost any machine shop they will say the same thing. Why ??? cause they dont want to be liable. its easy to be scared......BOO...being scared doesnt win races or make horsepower. .060 over is only .030 off the wall. which aint much on early blocks. some early studebakers v8's can go .250 over easy if ya got the balls to do it seen it done and it ran hard . olds blocks are some of the highest quality ever made the factory fit and finish is top notch. they didnt skimp on things they are heavy duty. early olds of course. i cant speak on later motors.
I've got a 303 that's already been punched for 324 slugs and wore out.....now it need's to be done again.. So, it'll go another .030 for clean up... Hopefully it'll live..
i agree with Bobert... with 50+ years of rust and pits in the cylinder walls you should be a little cautious. i only go big enough to clean up the bore. going the maximum right away doesn't leave any room for future rebuilds..ask Tony about that i know big bores is how they did it "back in the day"..but this is today. how do you really plan on using this engine? be honest. do you want to make big horsepower and win races? or do you want a good dependable engine to power your hot rod on the street , get you to the event and back and impress your friends? no offense to backyardbeliever , that's just how i see it
Wrong. When Oldsmobile increased the stroke in '57, they raised the block deck a like amount, keeping the pin to crown dimension of the piston the same. People have been making 345s from overbored 324s with 371 pistons for fifty years.
I stand corrected ......on that fact. Sorry.... im a 394 guy. Also i didnt mean to sound pro boring bar i was just giving one way of checking wall thickness. So does 303, 324, 371 and 394 have a 1.77 CH???? and what year 371's are you refering to early or late??
Very true.. We always run the risk of problems with mill's this old. They may have had superior casting back in the day, but we're dealing with old iron that's been subjected to years of abuse..What was "thick enough" back then, may not be now. Even if you sonic check the block, your only checking that area. There may very well be spot's that are thin that don't get checked. I'm taking my chances because that's all i have to work with.. IF i had another block, i'd do that one instead. Good luck.
I've got a complete 324 engine that I was going to s**** until I saw all of the interest on the HAMB. Now its sitting outside under a table. It ****ed a valve probably 20 years ago & sat in a rusted 55 Olds under a closed hood. If you ruin yours trying to bore it I could bring mine back to Michigan next april to Gingleville/Lake Orion.
wow...lovin the input....I was thinking early 57-58 371 piston which should be a 4" bore. The block which came out of a 23,ooo mile olds, transmission quit and the lady parked it, I bought the car from the original owner...anyway, have torn it down and want to rebuild it with some umph. like was I thinking I have read where in the late 50's-e 60's the possibilty of using the early 371 piston, buicks and lincoln's had a standard 4" bore from the factory in '54, which got my juices gearing up, so I beleive the 324's connecting rods would work and all I need is new pistons and pins ? Providing that there is wall thickness allowing a bore. By the way what was the bore on a GMC ('56) 370 OHV block? Wasn't that a 324 block to start with? (Movin/on) providing the possiblity of me destroying my lock I may take yo up on your offer....I'm in Ferndale.
coupla months late, but here's a previous thread... http://www.jalopyjournal.com/forum/showthread.php?t=144285&showall=1
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