Engine: Over bore

[kelmbaker]

A good friend put custom pistons in his '63 289 and came up with a 320 CI engine. He is of the old school....he just did it and the GT Hawk ran beutifully. It still exists.

I put together a 304 with an early truck block with minimal core drift (partial flow). It too, ran well, but not worth the custom 304.5 pistons instead of .060 standards 299 C.I.. Will sonic testing give me a mazimum overbore number? The biggest slug I can put in and stll have the engine stay together.

What will a full flow block safely bore to? Hank to crank advertises they could add another .25 stroke with welding (expensive). I figure a 363 or there abouts. but after lots of money.

Any observations? Thanks Kelly

[StudeRich]

A full flow block will bore to whatever the sonic testing says it will, they are very thin near the full flow filter. The Granetellis' had to search many blocks to find one that would go .093 over without breaking through, they are NOT all created equal.

I believe the Sonic testing will give you the Minimum wall thickness, it's up to you to come up with what remaining thickness you can live with.

But I don't understand what you are saying, you have been there done that and don't think it's worth the money for 304 pistons? Then why are we having this discussion? Same with the Crank, if you want to go fast, you gotta PAY!

[kelmbaker]

Biggest Stude V-8 that can be cheaply made.

The 299 was a great engine with no chance of a cylinder break though. The "seat of the pants" feeling between a 299 and a 304 pistons is not noticeable. Now the 320 is more powerful in all ways. a stroked crank and the 304 bore would result in a 364, or thereabouts. Definately a seat of the pants inprovment. No power adders, just welll balanced heads, cam, pistons, etc... The old way.
Does anyone know about the best blocks to do this to. Has anyone stroked a Stude crank (expensive, but could be done), the $$$ difference between .060. and .093 is just cost prohibited for the custom 093 pistons. .
Otherwise I want the biggest cube engine with a larger bore than stroke aimed alt low speeed torque and grunt. As I said, no power adders. I've read Didck Dotsun's stuff extensively, but Mr. Dotson is not interested in talking to me.

[Mike Van Veghten]

The largest bore is and has prooven for many years now to be the best of the changes that can be made to a short block.

Why...one reason, valves/combustion chamber.
Notice those nasty cutouts in the chamber sides in all Stude heads for the valves. The chambers badly overhang the cylinders..cause ugly flow. If you find a block that you can take to .093 or larger (!?), this will help the fuel flow into the cylinders...over and above any cylinder head work you have done.

And yea, cyl. #8 6 oclock thru 9 oclock positions will be the worst...though I've checked a few blocks that #4 around 6 oclock was also thin.

A long crank stroke is fine IF...you have the bore to go with it. AND...depending on what you are doing with the engine...street, drag racing, Bonneville, etc., even the heads I have that will flow 200cfm don't help a long stroke engine without the right camshaft....which unless you call me to buy a roller cam dosen't exist.

Will any of these combinations run...sure...but with stock heads, int. manifolds and cams, unless it's purley for the street, the money and time are a wasted effort...in my opinion.

Mike

[Alan]

It will go to 3 5/8" safely. I have bored them out to 3 3/4". But before sonic testing I have hit water before getting to 3.750". It is senseless to bore a good full flow block out so big in one shot. Go .030", .060", .093" .125" then .1875". That will give you 500,000 miles of fun. Or find some one that has a clapped out block and check it.

[kelmbaker]

I want to build a cheap Stude V-8 with the biggest bore availabe I want the heads to be cleaned up and unshoulded, but not given a race style job as this is a street engine. I have a Lionel Stone intake I want port matched. I have Lionel R-3 headers I want match ported. The carb is a Edlebrock and the distributor is a Petronix. R-2 baffle oild pan and opening up the oil returns in the back of the heads. The cam?/R2+.
To me this is the cheapest, most effecient method of gaining a true 260 HP naturally asperated Stude V/8 with the manners of church mice (except when kicked in the tail). So radical overbore is out, as is stroking. Gets back to basic. arefully port match and balance everything, let it breat and give it good fire. I welcome comment.

[kelmbaker]

Sorry I re-read your step method to large bore to late. My machine shop will chage me up the nose to bore, then test, then bore then test. They charge me to walk in the door. I don't blame them they almost went under and they've been around 60 years. No more Mr. Nice guys....