Thread: 2 Bolt Block

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Hello, I am new to this forum but been a mechanic all my life.

I am currently doing a frame off restore on a 1974 corvette that was my fathers. He passed away two years ago and I inherited the car. He was going to do this when he retired so I am fulfilling his wishes. The car will pretty much be driven only to club meetings or shows so here is my questions.

When I got the motor apart he apparently had some work done to it as it is only a 2 bolt block and not the original one. It is currently .030 bore. It did have a nice B&M tranny though. So back to the question. I plan to build a 383 stroker, already have a nice set of AFR 210 eliminator heads complete and ready to go.

Should I get a new 4 bolt block and start fresh there or should I have splayed caps installed and go .040 on the bore. I am on a tight budget but the motor needs to be built right. The plan is to have about 500hp and a good shot of nitrous with it.

What direction should I go on the block? The frame is heading to powder coat next week.

Thanks in advance

Jim

Being a Ford guy, I'm used to putting splayed caps on everything...Never had a bit of trouble with them.

O.K. I am awake and thinking a bit clearer today, so I will pull my head out of the gutter and try and answer this correctly. 500 horse on a 2 bolt chevy is pushing it, then after you put the spray factor in its over the top as far as the 2 bolt main could handle. I would not say it wont handle it, I am saying you will be taking a big chance. Go with either having the block splayed or get another 4 bolt main core and build it. I would not run a stock cast crank under tose conditions either, that is probably in that block too.

Oh sorry I wasn't very clear. I am definitely going to go 4 bolt but what I was asking was that since I have the two bolt block already should I go ahead and just install splayed 4 bolt caps and go 040 on the bore. I plan on using a Lunati balances rotating system. It will be built with all the strength needed but I was just wondering about if I should waste my time with this block or just find a 4 bolt core to use. I have heard that ading splayed four bolt caps to a 2 bolt block will be stronger than a standard 4 bolt block. Is that true? And is it ok to go the 040 on the bore?

Thanks

My brother did his own splaying job on his 2 bolt block. I am not sure what he paid for the kit I will look that up and post it here. That would be a safe route to travel for sure, the kit does claim they are stronger then a stock 4 bolt cap.. 90.00 a set but they need machined after install, but you are gonna have the block there anyway. here is eagles quote,

Bulletproof your engine's bottom-end with Eagle Specialties.
These Eagle billet steel main caps offer superb strength at a reasonable cost. Eagle main bearing caps improve performance and reliability by eliminating main cap walk and reducing main bearing bore distortion. These main caps are designed to fit Chevy 2-bolt blocks with machine work. Eagle main caps include a drill bushing, 6 bolts, and 3 main caps. Please note--the engine block must be drilled for 4-bolt conversion and line bored after main cap installation.

Hey Jimmyz, that looks just like my '74 coupe. Same condition too. Body off on a dolly. If the block is in good shape go ahead and splay the caps. Not a problem, but probably an added expense. In the SW Ohio area there are still a good number of 4 bolt blocks available. I built a 500 hp 383 this winter for my C3. Just buy a forged rotating assembly and don't assume it is balanced. Have it balanced at a local quality speed shop. The factories do sometime make mistakes. Your local guy will more than likely catch them. Good luck.

This is from the school of hard knocks. Don't go with the factory 4-bolt main caps. Buy quality aftermarket main caps and have block machined. As for the .040 overbore, have the block honed by a machine shop that has the diamond hone setup. They make a great finish on the bores. Also, have them use a honing plate.

Hey jimmyz, I forgot this earlier. I am running AFR 195 eliminators on the 383. If all you are doing is building a great running street car AFR reccomends the 195s.

A 2 bolt can be better than a 4 bolt if the caps are splayed. The heads are on the outer edge of not to great on the street , I think.
A budget engine would be the engine stroke to 383....Heads might be a little big for street ,IMO, but if you got them slap them on. At the stage its at you might do better concentrating on the frame and the suspension.

Thanks all, Yes I have the heads already. They were such a smokin deal that I couldn't pass them up, never been mounted, in the box fully ready to go. I have seen quite a few 383 builds with the 210 head that still run pump gas if done right. I know that in order to get these heads to flow as designed I will probably need to go solid roller cam.

Jim

If you are going just run the car just on street I would not waste the money go to four bolt setup...