I'm confused, it sounds like you want to build a 400, a 377 or a 383? What parts do you want to keep from each engine?

My first preference is to use a 400 block with 400 piston (of course), then use the LT1 components from my '93 Vette, e.g. LT1 intake, heads, rod and 1 pc seal crank. Essentially a 377, more or less.

I plan to go with the Isky roller cam, p/n 261272/282. The heads will be reworked to accomodate 2.00/1.56 valves and ported.

My other option (alway a back-up) is to keep what I have block wise, but go with a Scat 9000, 3.75, 1 pc seal stroker crank. I haven't fully thrown this option out the window yet due to unknown potenital for 400 block integration with the LT1 components. Should I go this route, I'll probably back off on the cam to an Isky 261265/272 for the stroker crank will not provide the higher RPM like a 377. The smaller cam will give me more grunt at the bottom.

There may be somebody that knows about this interchange. The 377 sounds very possible.
I think that the only real problem would be in the head to block area.
you could go down to the local parts store and borrow an Lt1 & 400 head gaskets. Place them on top of each other and check to see if all the water passages line up.

That looks like the biggest concern I see, and easy to check too!

That's a good idea on comparing the head gaskets. Better than having another block stuck in my garage, of which several already reside.

Did some research and found out the following.

1. LT1 head gaskets are not interchangeable with Gen I SBC head gaskets for they have different water passages due to the reverse cooling.

2. To make it work, you'll need to weld an aluminum plate into the reverse flow passages; then provide new routings to interface to the Gen I passages. Plus the oil passages aren't compatible either.

3. Also, the LT1 has it own set of steam holes locations that will need to be coordinated with the 400 block holes.

Sounds like three strikes to me. But then again, I could buy a new set of heads that interfaces with the 400 block. Then I can interface the LT1 intake to these heads per "LT1intake.com". This would allow me to get rid of the Optispark and have a normal distributor.

Dreaming . . . . OK, it'll probably turn out to be a nightmare. Anybody with a bucketful of $$$?

Guess it's back to the stroker crank. Probably be better in the long run with all the hills around here.

Jon,
This subject comes up every 2 weeks, it seems. Why don't you put together a subject in the Knowledgebase about it?
Thanks,
AngliaBob

A 350 with a nice cam and intake with a new injection system would give you the pleasure in the hot rod without the exspence and work with a 383

A 377 is a great race motor but least in hp and torque. A 383 is a bad combination and is built by people who do not want to spend the money on a 400 replacement crank. 350 cranks are cheap and easily accessible. Thats why people build them. The 400 built correctly will turn 6500 rpm with a stock cast crank. Give you an extra 27 ci and 35 hp with a 70 cc head with a flat top piston. A stock 5.7 350 rod will give you more dwell and hp but may clip any .500 lift or larger cam. Using a cap screw I beam rod will rectify this problem.

A 377 is a great race motor but least in hp and torque. A 383 is a bad combination and is built by people who do not want to spend the money on a 400 replacement crank. 350 cranks are cheap and easily accessible. Thats why people build them. The 400 built correctly will turn 6500 rpm with a stock cast crank. Give you an extra 27 ci and 35 hp with a 70 cc head with a flat top piston. A stock 5.7 350 rod will give you more dwell and hp but may clip any .500 lift or larger cam. Using a cap screw I beam rod will rectify this problem.

wrong, a 400 is externally balanced and at a higher rpm the crank starts to flex. In order to keep this from happening you must keep the rpms well under 6500. My 377 will do 8000 easy. I have a 7500 rpm limiter in the msd because during burn outs i was taching out. Ive had em all 350, 383,400, but the 377 pushed my car into the 10.90s from a 11.10 with a 383 and 11.22 with a 400.

you want gas mileage. i got a 4.3 v6 for sale that ill build however you want it and send it to you.

you can buy a 383 stroker kit balanced and all for around (depending on you generation of engine) Grand on jegs

Strike #4 Also your 1-piece rear main seal crank will not work in a 400 block.