400 longblock needed

[ITSSLOW]

I just found this online

400

A 400 in³ small-block was introduced in 1970 and produced for 10 years. It had a 4.125 inch bore and a 3.75 inch stroke. Initial output was 265 hp and was only available equipped with a 2-barrel carburetor. In 1974 a 4-barrel version of the 400 was introduced, while the 2-barrel version stopped production in 1975. 1976 was the last year that the 400 was used in a Chevrolet Passenger car, available in both the A-Body and B-Body line. While popular with circle-track racers, the engine was prone to cooling troubles if cylinder heads without steam holes were used. The 400 produced a lot of torque at low RPMs compared to the other displacements and was used primarily in pickup trucks and the large B-Body (Caprice/Impala) but also found use in Vans. The 400 was eventually discontinued due to its inability to meet EPA emission regulations in place in the early 1980s.
The 400 was unique compared to all other displacements for 3 reasons:

• Due to the siamesing of the cylinder bores in the casting - there was no space between adjacent cylinder liners - this block was rather rigid and not prone to the cylinder bore flexing of the other displacements.
• This block used a much larger 2.65 inch main bearing assuring that crankshafts from all other blocks would not fit without special oversize bearings.
• This is the only small-block that used a 5.56 inch long connecting rod compared to the 5.7 inch connecting rod in all other displacements.
• The 400 came with 4 bolt main bearings in 1971 and 1972 only.

While Chevrolet never produced a factory performance version of the 400, it is highly sought out among racers who participate in the very popular 406 racing class - so named for the displacement created by a minor overbore. Destroking a 400 block with a 350 crankshaft creates a 377, a popular combination for dirt track racers. 400 blocks are nearly impossible to find as salvage today and as such the racing market is fed by 3rd party manufacturers who offer improved versions of the block.

[81DaytonaPaceCar]

Nice write up.

400s are BAMF.

377s are badder.

'Course they make stroker cranks for 400s too.

A 454 small block is easily done.

[ITSSLOW]

Nice write up.

400s are BAMF.

377s are badder.

'Course they make stroker cranks for 400s too.

A 454 small block is easily done.

Unless someone wants to give me a 350 crank or a 400 stroker kit I think I'll end up just putting it .030 over (408) when I rebuild it if I decide to.

[81DaytonaPaceCar]

Unless someone wants to give me a 350 crank or a 400 stroker kit I think I'll end up just putting it .030 over (408) when I rebuild it if I decide to.

A 350 crank should be very easy to find. Maybe, what, $20, $30 or so?

And 406s are good too.

Ah, you can't lose either way...lol...

[ITSSLOW]

A 350 crank should be very easy to find. Maybe, what, $20, $30 or so?

And 406s are good too.

Ah, you can't lose either way...lol...

I've got 2 350 cranks but one is for a 1pc rear main and one is for a Vortec 350 (96ish+)

[81DaytonaPaceCar]

I've got 2 350 cranks but one is for a 1pc rear main and one is for a Vortec 350 (96ish+)

Sounds like good trade bait to me.

The 400 have a rope main seal?

I hate rope-freakin'-main seals.

Pontiac did that for waaay too many years.

[ITSSLOW]

Sounds like good trade bait to me.

The 400 have a rope main seal?

I hate rope-freakin'-main seals.

Pontiac did that for waaay too many years.

I honestly don't know. The motor has 68k orginal miles and is being tore out of a car as I'm typing this. I went for a ride in the car at like 9am today in the car. Next weekend I go and get it. He said for another $350 I can have the transmission. I think I'm going to turn that down because its an auto and my car orginally was a manual. Although I could make the 3rd pedal spring loaded and make it a nitrous pedal.......

[MrMojoRisin681]

I'm putting my battery in my trunk within the next week. As far as the motor mounts go, there might already be mounting holes in the subframe for them. You could ask over on transamcountry.com Be prepared to take some shit for putting a SBC into a pontiac though. I get shit for having my 350 in mine, and it came from the factory that way.

[ITSSLOW]

I'm putting my battery in my trunk within the next week. As far as the motor mounts go, there might already be mounting holes in the subframe for them. You could ask over on transamcountry.com Be prepared to take some shit for putting a SBC into a pontiac though. I get shit for having my 350 in mine, and it came from the factory that way.

I'm not scared! F**k um! I'm a bastard cause I want to do something other then a 350? F**k those guys! lol

[MrMojoRisin681]

No alot of them just believe that Pontiacs should only have Pontiac engines in them.

[ITSSLOW]

No alot of them just believe that Pontiacs should only have Pontiac engines in them.

Well it'a a PITA to afford 3 fbodies at one time, ya know? but I am only one gen short of a full house......

[Yoeasy69]

woot for the full house!

good to see you found out what it should be..

a 4 bolt 400 sbc is a really beautiful platform for some serious fun time. just do it right.

the water jackets in them are a bit screwy.. but it will be fine.

[ITSSLOW]

woot for the full house!

Yeah, I really need to update my sig

[wezeles]

ya the 4 bolt isnt as nice as the 2 for the 400 block but at the right machine shop when you do decide to rebuild they can fix the glitches... and you can only stroke out the stock 400 block to like a 421 safely anything bigger than that you need a aftermarket block... have fun with it and destroke it to a 377 get some revs and still keep the cubes...

[ITSSLOW]

ya the 4 bolt isnt as nice as the 2 for the 400 block but at the right machine shop when you do decide to rebuild they can fix the glitches... and you can only stroke out the stock 400 block to like a 421 safely anything bigger than that you need a aftermarket block... have fun with it and destroke it to a 377 get some revs and still keep the cubes...

Well online it said from1971-72 were the only years 4 bolts were produced. It didn't say 100% of them were 4 bolts. As of right now I have no plan on building it up cause the thing runs amazing and doesnt leak a drop