SB Chev 355 or 406
 

building a street and strip engine and was wondering on the pros and cons on these two engines . I was told to stay away from the 400 . any comments ?

Re: SB Chev 355 or 406
 

400 externally balanced,and do you see many out there,,i dont ,so that tells me enough ,,,,

Re: SB Chev 355 or 406
 

There is nothing wrong with the 400, with some minor upgrades that Chevy could have done. I ran one for years in my 67 Camaro, with small valve heads and cam from a 350. The car weight was 3100 and with 4.56 gears, ran 11 flat in ugly air and low 10.70's in good fall air.

Re: SB Chev 355 or 406
 

I'll add to the mix. How about a 383?

Re: SB Chev 355 or 406
 

Have had a ton of 355's very reliable low maintenance motors. Roller cam Brodix track 1's and 13.5 to 1 comp 10.30's all day long in a 3400 pound camaro . Had a tunnel ram and splits on one in my 70 camaro back in the 90's ran. 9.80's at 3400 pounds ! Yiu can buy everything reasonable for one .

Re: SB Chev 355 or 406
 

i have some parts in stock for the 355 and the 406 but none for the 383 such as the stroker crank to fit the 350 block , i believe the rods are all 5.7

Re: SB Chev 355 or 406
 

If you build a 383, you must cut the mains, of the 400 crank, to 350 size. Then you use standard pin height 350 pistons with a 400 rod. Good torque engine for the money. The 350 block seems to have better head gasket sealing. But nothing beats cubic inches.

Re: SB Chev 355 or 406
 

I hate the 400 blocks have seen them crack just bolting a toque plate on. The the only block when it comes in the shop I get paid 100% up front. Pretty frail block compared to a 350 block.


Using stock 400 rods in a performance 400 build in really not the hot set up !!!

Don't wast your time having some one grind an old 400 its some times a waste of money as when grinding a crank that much the oil holes do move closer to the radius.

I don't recommend using a externally balanced crank in a performance build.

If your building a budget build you can buy a Scat 9000 series crank for around 200.00 That will internally balance and they have one for a one piece seal block that will internally balance no problem , Scat 6.0 I-Beam rods with 7/16 bolts 300.00, Pistons Wiseco has a good deal on there Protrue series pistons and rings for about 425.00

If you can find a one piece seal block and use GM Hot cam 234/242 and buy there roller lifters as kit makes for a cheap roller cam and lifters. The Dart SHP 180 CC runner heads 64CC chambers.

I have done that build many times with very good results.

Re: SB Chev 355 or 406
 

Street,strip, bracket build a 350. There is no engine better for the buck, with incredible durability. If you want to build a 400 buy an aftermarket block now...or later when you waste a lot of time and money.

Re: SB Chev 355 or 406
 

X10000000000000 I have seen a lot of guys spend good money on bad when it comes to OEM 400 blocks !!!

Re: SB Chev 355 or 406
 

Build a 383....best bang for the buck in a street engine.

Stock 350 block...none of the 400 block problems...

I built lots of them....and with all the piles of inexpensive rotating assemblies out there now it's a no brainer and easy to do. You don't have to use a Stock GM 400 crank or the short GM 400 rods...

Only minor issue is rod to block and cam clearance and it's not much of a problem with any stroker type h beam rod.....

Stroker type rods usually clear a small cam with no problems.....

Easy to check during a preassembly...Only 2 pair of rods ever get close to the cam lobes anyway...




A decent stock block with little or no core shift just needs a little grinding at the bottom of the cylinders for the added stroke..

The cam to rod clearance is real easy to check.
I used strips of cardboard, or clay and a mirror....

A 383 has great torque and a perfect street strip engine...




400 blocks are nothing but problems...

Re: SB Chev 355 or 406
 

Don't ever go by core shift its a poor indicator compared to actual cylinder placement when the mold is put together.

I have seen block with zero core shift fail a sonic test and I have seen many blocks with very poor cores shift pass a sonic test.

The only real advice is sonic test for true results.

Re: SB Chev 355 or 406
 

The reason I mentioned core shift is on one engine I built it was off so far that rod clearance at the bottom of the cylinders was way off from one side to the other. I had to use a different rod than what we originally picked to get clearance without excessive grinding at the bottom of the block but only on one bank.... The cam hole showed the offset where it was machined flat at the face and that is a real good indicator...


Factory blocks can be way off...for sure...

Re: SB Chev 355 or 406
 

I wouldn't build a 400" without a Bow Tie or Dart block.

Re: SB Chev 355 or 406
 

Again don't go by the cam plug hole its not a good indicator for cylinder placement. Sonic test is the only way to go.