well what do you guys think i should go with:

350 small block or 400 small block

please any suggestions would be great.

 

I'd go with the 400 for the extra cubes, but steam holes need to be drilled into the heads.

 

If you use the stock heads or any heads designed for a 400 the steam holes will already be in the heads, so don't let that scare you, plus the holes are easy to drill.
The 400 is the way to go.

 

400's don't overheat without the steam holes...both my friend and I have 406's and with a combined 13 years of both engines on the street...under all weather/driving conditions (except snow), we have had no problems...

Except recently, when my friend was racing someone on a long lonely stretch of road and he had it pegged at 6,000 rpm for about 3-4 minutes, then turned off and shut it off quick in his garage, his coolant boiled over...can't figure out why

That is what happens with a Turbo 350 and 3.73's...top speed of about 125-128...he needs overdrive

This story is not an example of overheating...cause it didn't and runs fine....

 

Duh, more bigger equals more better. my 406 doesn't overheat without steam holes either, but i would have drilled them if i noticed they weren't there. it was 93 today and it runs wherever i set the fans to come on. i like to run it between 180 and 190.

 

My dad did a 400 in his 87 Montie SS. Dart heads, dynomax headers full quiet exhaust, edelbrock intake, 750 holley. Runs 12.80 with some more tuning to go. I am not sure how big his cam is but it idles good.

Rich

 

400's are a Good motor, easily a 12 second motor with little work done. As long as your gonna stay carbuerated, go 400

 

im currently building up a 400 its supposed to be about 450 hp they sound like a really great motor ive heard mixed opinons on the holes needing to be drilled into the heads. really theres no replacement for displacement. and dont let anyone talk ya into that 377 garbage if you have a good 400 go with it why reduce cubic inches. good luck man chevy's rule

 

350 has more potential and you can't rely on those 400 castings to hold up to a .30 or more.
but the larger bearings are nice.

 

Actually, you can bore a stock 400 block to .040. Don't go more than that...

And drill the steam holes. That is why 400's have a reputation for overheating, because people didn't drill the holes in the 350 heads that they swapped on.

If you understand the siamese cylinders, you will see why the holes should be there. I can vouch for 3 seperate 406 engines with steam holes that have no problems with overheating on the street. 150K between all three so far and counting.

 

Amen to that,88TPI406GTA hit tha nail right on the head if you want to avoid overheating drill steam holes into the heads that is the biggest concern with overheating. as far as i was talklin about the 377 i was talking to a buddy at work that has one and he says its a piece of $hit till he gets to 9000 rpms. http://www.ryanscarpage.50megs.com/combos14.html combo 101 shows a 406 487hp at 5500. not a bad setup,no replacement for displacement. get your steam holes drilled in the heads and go with the 400.

 

400!!!!!!!!!!!!!

 

If you go with aftermarket heads (wich you should) the steam holes are usually there....otherwise all it takes is a1/8" drill bit..match the holes to the gasket.

 

Get a 350 and stroke it to a 383. I just put a deposit on this setup tonight (see sig). It desktop dynos at 580HP and 523 lbs TQ. You can afford the best of parts with a 383 but a 400 can get costly.

 

Thats a tough 350...you'll have to let us know how it dyno's in the real world.
Are you building this for dual purpose? Pretty high compression for pump gas. But what do I know....only a little.

 

I am going to drive it on streets occasionally. I will be able to get away with pump gas because of the lumpy cam. Its a roller cam with the dur @ .050 248/252 and lift .606/.585. I already went over this with the engine builder. I wanted to go as high as possible with compression but still be able to use pump gas.