Was wondering how far you have bored your engines?
What is the most you feel comfortable boring too?
What are your thoughts about boring your 350? Negatives vs Positives?

Rodney

Hi Rodney,  never really had any negative thoughts about boring an engine, only that i know that it can only be bored out so far, and then, its on to another engine..  Dad's 76 vette has been bored a couple times, the original block, was first bored 30 over, then again 40 over(no, not 40 over the 30... a total of 40 over i think? maybe it was 60 over?... but, maybe it was 40... too long ago).  I really don't see a "bad" side to boring, it gives your engine a new lease on life, especially our older engines that don't really reap the benifits of the technology of today's engine, i mean, who would have thought that an engine would go 200-300 000 miles without a rebuild??.. 100,000 was a long time on an engine back in the 60's and 70's(80's too).  I've always been told that 60 over is pretty much the limit on a small block chevy... beyond that the cylinder walls are a bit to thin and the water jackets are prone to cracking through??... something like that... no doubt someone else in here would know  a bit more than i :)

 

 GO for it!  40 is no problem. Other things factor in when going more than that.

.060 is aboot the safe max on a 350 block. Different blocks allow more or less, depending on the wall thickness to begin with. The earlier blocks seemed to handle a .060 with no problems. Mid-late '70s & up not so much. The best way to determine a safe bore limit is to have the block sonic tested. This will tell how thick the cylinder walls are in each hole.
I built a 283 that I bored .060 over, and had no problems with that one, but it was a '66 block. It had 12.5 pistons, and a Manley copy of the Duntov "30-30" cam....that thing would scream in my Chevelle!

If you're using a "standard" block, that has no MAJOR cylinder wear, the thing to do is go only with a .030 over on the first build. That leaves ya room to grow in the future, if needed.

I finally found out what my final number is. The block I ended up with was an assembled engine that had been sitting for the last 15 years. When we removed the heads the cylinders had rust in them. Wasnt sure what it would take to clean them out and even thought maybe it would be my second wasted block, remember my first one was cracked across the lifter area. Well in order to bore it, first it had to be decked so I was worried that we would have been wasting money if it wasnt a usable block. I told him to go ahead and see what happens. Well I stopped in last night before we headed to the beach for the weekend, (yes I decided I needed a weekend on the golf course to ease my mind a bit!) and finally got some good news. The block has no cracks, ended up cleaning up very nicely at .040! We were going .030 to start with since we are making it a stroker engine. Now I told him I need the engine completed by the end of February. I want to change it out in the month of March. I still hope to have it running and on the road some time in April. I am hoping a good golf weekend helps clear my mind so I passed on working on it this weekend. Well thats all for now. I should have some more updates in a few weeks.

You deserve a break, Rodney! Looks like things are coming together nicely!

Well heres an update on progress of the engine build. So far nothing has really happened! so far the block is still sitting decked and bored. We did order and received the camshaft. We went with an Erson cam flat tappet hydraulic. Quick numbers are #E113421S, lift is .472 intake and exhaust, durartion@.050 is intake 228 exhaust 235. center line is 106. He has completed the seats on the world heads but hasnt assembled them yet. I told him this week that my plans on installing the motor had changed and I need the engine next weekend to put in. I decided to install the engine first then the tranny after that. This way I wont be trying to align the trans to engine over the new painted fenders. He thought he could have it done by then. He still needed to order the stroker crank and new pistons/rings. I am going to help assemble the engine one night next week and then he will show me the steps on degreeing the cam. Hope it all works out. New carb arrived today so I think I am good with almost all the parts.
Rodney

Can't wait to hear that mouse ROAR! 

Hey Rodney,

This is gettin' good! I hope the rest of it goes smooth.

BTW, what carb. did you decide on?

Kevin

Kevin, It just showed up yesterday on the front porch. Its a holley 750 vacuum secondary with electric choke. Should be ok for this application. Thought about mechanical secondaries but since I plan on just driving and no racing I didnt want to have to mess with extra setup and adjustments. Hope it was a good choice. I plan at some point to try different intakes because I know I am being held back with a edelbrock performer. Big decision right now is should I go with solid motor mounts or stay with a stock poly type mount. I need to place my order tomorrow sometime.
Rodney