a 305 to a 350.....a 350 to a 400...... How hard are the 400's to find.... Thanks

 

That's kind of a vague question. 400s are usually harder to find than a 350 I would think.

 

a 400 would prolly be the hardest to find. followed by a good high nickel 4 bolt main 350. then comes the 2 bolt main, roller 350's(easy to find) then the 305's which most can be aquired for free.

Out of all of them, i'd take a 4 bolt main high nickel 350, My opinion the best block to start off with... tough wise. I'd pay upwards of 150-200 bucks for one that was in good shape, and didn't need much machine work... just for the block.

 

A 305 has a 3.740" bore and a 3.480" stroke.

A 350 has a 4.000" bore and a 3.480" stroke.

A 400 has a 4.125" bore and a 3.750" stroke.

That's where they're different.

400 blocks aren't too hard to find, they're just a little weak. They only came with 2-bolt main caps and have thin cylinder walls. You can strengthen them sufficiently by using main studs instead of bolts and some block filler. I'd agree with Pony Killer that a high nickel 4-bolt 350 block is going to be your best bet, I'm currently trying to track one down.

 

Bore and strokes above are correct. Thin cylinder walls on 400...incorrect. 400s only came in 2-bolt...incorrect. 400 weak...incorrect.

The 400 has both 2 bolt and 4 bolt mains. It is true that a studded 2 bolt is the strongest. The 400 block has siamesed bores. Because of the size of the bore, 400s do not have a waterjacket between the cylinders. The main problem with 400s is people not drilling the steam holes in a head that was not a factory 400 head. This causes overheating and possibility of cracking the block. And with the stroke of the 400, you will not get more torque form a 350. That is why so many people stroke a 350 for a 383.

If you can find a 400 reasonably, get it. I hate to be cliche...but..."There is no replacement for displacement."

The HP curves are almost exactly the same, but the gain in torque will make you happier on the street and at the strip. Just something to chew on.

BTW, if you want casting numbers of years and mains of the 400, pm me and I can send them to you.

 

Yeah, I got mixed up.

They came four bolted, but never with a steel crank.

 

I have found 3 400ci blocks in a week. They aren't that hard to find. The problem is all the owners would sell their first born before they would give up those blocks.

 

I have two 400s sitting in my garage, i picked them up at 50 bucks apiece

 

LET ME KNOW WHERE YOU GOT THAT DEAL! I wouldnt mind having a couple of blocks to play with. $50 buck a pop....sign me up!

 

While most of the parts used in 350s and 305s are interchangeable (except those affected by bore differences, the 400 parts are not usable in any other blocks. Your 350 and your 305 are the same basic block (I believe based on the 327), and the others are correct in that the bores are different. The 305 bore is 3.7360 inches. The 350 bore is 4.0000 inches. The stroke is the same in both engines. Another difference is the intake and exhaust cam lobe lift, which also differ from 86-90 and then from 91 and later. Also affecting cam lobe lift is carb or f/i. Valve angles for both are the same. I belive the lift on the 305 cam was slightly more radical. The cranks are the same, forged.

 

OK I know I´m stoopid, but how can I tell a difference between
2 and 4 bolt 350!

 

pull off the oil pan. then look at the main caps holding the crank in the engine. finally, count how many bolt are holding the main cap to the engine block. the rest is self explanitory.

or you can check the casting numbers.

 

Ahaaa!! Thanks! I think I will go with the numbers!
Can you tell me what should I be looking for or should I post the whole number on the board?

 

you should be able to find what you are looking for at www.mortec.com

 

WOW! Thanks! Thats a great page!:hail:

 

Hey Nate , Thanks a bunch! That's exactly what I asked for, "bores and strokes".

 

you also have to remember the main journal sizes are different. I dont have the numbers in front of me or I would tell you. I know the 400 has the large main. Also the rod length on the 400 is 5.565 when other small blocks have a standard 5.700 connecting rod.