Do my main bearings, pistons, rings, and rod bearings all need to be .030? And does it require a new crank?

Thanks,
Matt

 

Can't be done, not that anyone would particularly want to.

305 bore is 3.736", stroke is 3.48"; 307 bore is 3.875", stroke is 3.25". Not many 305s will go .060" over, let alone .140" over; and even if it did, it wouldn't make a whole lot of sense to smallify the motor by putting an even smaller stroke crank in it.

A 305 at .030" over (bore), the standard amount, has 310 CI. CID is not affected by grinding the crank, assuming the journals are ground on the original centers; so the bearing undersize has no effect on the engine size.

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"So many Mustangs, so little time..."
ICON Motorsports

 

So would I want to buy all those parts with the .030? I want to rebuild my motor and was just trying to find out what numbers I need to put into the selections at http://www.northernautoparts.com/Pro...uctModelId=717 .

Also I was wondering what option I should select for the oil pump. I want to go with the Comp Cam with 252 dur.

Thanks,
Matt

 

For the crank bearings, you need to get your crank turned first, then buy the bearings for the sizes it ends up. If you're just rebuilding an old motor that ran but smoked alot or whatever, not a blown-up one, then chances are the crank will be OK at .010"/.010". But, don't buy parts until after you've got the rough-in machine work done.

Block (piston & ring) size is a different matter. You need to have the block bored & honed to fit the pistons correctly, but you need to be sure that your block is in perfect shape at that overbore, which you can't do until you bore it. If you bore the block (you'll most likely need to) then you'll need oversize pistons & rings, probably .030" over. The best thing to do is to get it bored most of the way out (like to .028" over), make sure it's good there, then you can buy the .030" over pistons with assurance they'll fit right.

If I was building a motor from that page, the first thing I'd do is find out how to lose the dish pistons and put the F-M flat-tops in there. I would not recommend any of those particular Comp cams, they have better ones now; I'd go with one of their Xtreme Energy series, depending on what the rest of your motor is. I'd get the brass freeze plugs, moly rings, high-pressure oil pump (NOT high volume), the better OP drive rod, Fel-Pro gaskets, and the Manley timing set. I'd leave the F-M bearings in there.

Look at this one, it's got the flat-tops, and already has most of the upgrades I am suggesting; except, see if you can get them to sell it less the cam, and get one of the others as described.

http://www.northernautoparts.com/Pro...?ProductId=705

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited December 03, 2001).]