400 engine and 400 tranny

[nbpro]

we got our hands on a 400 engine and 400 tranny. it's a running motor, so we'll see exactly what we got when we get it up here. so far total cost,0+ time and effort of emails and phone calls so I'll probably have lots of questions. Thanks in advance.
heres pics

[Dru]

Cool. If you have to go through it, you might consider a 350 crank, its the road less traveled with 400 small block builds, but it gives the old 400 a lot more rpm's with those bigger pistons, making it a 377+ cubic inch, depending on bore.

[nbpro]

Originally Posted by Dru

Cool. If you have to go through it, you might consider a 350 crank, its the road less traveled with 400 small block builds, but it gives the old 400 a lot more rpm's with those bigger pistons, making it a 377+ cubic inch, depending on bore.

thanks will look in to that

[3r!c84]

i seen the message. good fine. good threw it and put a bigger cam and check the heads over. but vortecs if money is there. need to have them drilled tho.

guess i talked you into a 400 some swear by them. some swear at them.

you will like it

[nbpro]

yes the steam holes need to be drilled
the edelbrock performer RPM heads will provide huge amounts of torque on
a well prepared 400 CI engine, they will outperform the Vortec heads if
both are unported. AFR Cylinder Heads are sweet to
thinking about destroking the engine

[Allensracing]

anybody can drill the holes, its not a precise operation. just use the new head gasket to locate the location, and drill them with any drill. all they do is allow steam and trapped air to escape from between the cylinders

[nbpro]

yep

[3r!c84]

what heads are on it now?

[nbpro]

not here get next weekend cuz of family problems

[3r!c84]

Right right. Ok let me know next week
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[BigBlocksRule]

I can't understand why anyone would want to lose displacement on an engine by destroking it. If that theory held water, there are a lot of folks out there making a mistake by building a 383 with a 400 crank.
Stick with stock stroke, toss the factory 400 rods - they're the weakest of the bunch - and get a set of stockers resized. Vortec heads and a decent cam will give you all the power you want.
The destroker will only rev a few hundred rpm's over the 400, maybe a fraction quicker - and he'll be behind you, trying to catch up. Extra cubes = extra torque
BTW, the factory 400 crank is nodular iron, same thing Eagle and Scat uses in their "cast steel" cranks.

[LONGHAIR]

Originally Posted by BigBlocksRule

I can't understand why anyone would want to lose displacement on an engine by destroking it. If that theory held water, there are a lot of folks out there making a mistake by building a 383 with a 400 crank.

Yes, stick with the stock 400's longer stroke, that gives you the torque that is needed in a comparably heavy truck.
The "problems" that people complain about with 400s are about cooling...changing the stroke isn't going to do anything about that, so there is no point to changing it, and giving up torque in the process.

Originally Posted by BigBlocksRule

Extra cubes = extra torque

Actually the extra torque comes from the length of the stroke not from the cubic inch increase alone.

[BigBlocksRule]

Longhair, that's the way I always looked at it, but there was a very good discussion at Team Chevelle a few weeks ago regarding this topic. An increase in bore size with stock stroke gives almost identical numbers to a smaller bore size and increased stroke.

At any rate, I sure don't see any reason to give up ANY power, particularly in a heavy truck.

The 400 overheating issue comes mostly from folks that don't take the time to drill the steam holes, PLUS trying to cool a much more powerful engine with a factory/small cooling system, mostly the small radiator.

[Dru]

Destroking doesnt help with the heat, obviously. I dunno how many of you have been into building motors for awhile, but there have been quite a few 383/377 shoot-outs publicized for people to read, and the 377 comes out ahead in power, with a slight loss in torque, and youll end up with more power than most people are pushing out of a mild 400.

These half ton trucks don't weigh that much, infact I'm pretty sure my 77 Corvette weigh's more, for example.

400's rpm range is more like a big block, by building a 377, you unshroud the valves with the bigger pistons, yet retain the small block rpm's, you will gain a lot more than a few hundred rpm's.

The slight loss in torque over a 400 is negligible. The 400's steam holes are drilled at an angle, but I'm sure nbpro already has the info.

Just for the record, I wouldn't even waste the time to build a 383, they just became popular because people could make use of their plentiful 350 blocks, and get more power out of them.

The 400's can just be a little doggy to me, I like them, but I also like a small block that screams, just my personal opinion.

[BigBlocksRule]

You might end up with more power out of a built 377 than a mild 400, but if you build 'em with similar parts, the 400 will hand the 377 it's butt.
We're talking about 1/4" stroke change, not the difference between a 283 and a 400. You will gain a few revs, but not much. Piston selection is much more limited, plus you get to buy special bearings or bearing spacers...just don't see the reason to build something you have to spin higher (increased valvetrain wear/stresses) to get similar power out of.

My '81 Corvette comes in a 3230lbs - I don't think I've ever seen one of these trucks come in anywhere close to that number unless it had been gutted.

[Allensracing]

I used to circle track a 68 chevy truck. I ran several motors, ranging from a 350, to a 377.
I used all factory block crank and heads to build the motor per class rules.
I used a 11:1 "badger" piston, stock 5.7 rods, open chamber smog heads and a cast iron intake with a two barrel. the block was a 4 bolt main, but a 2 bolt would have worked the same. it had a .540 lift solid cam. the 377 ran at the exact same temps as the stock 350 we had previously used. the 377 was completely balanced and blueprinted. we did run race fuel. it was estimated from the trucks weights and lap times that it made about 400 horsepower in that configuration. it spun 7000 rpm most of the race. it rarely fell below 5000 rpm.

at the end of the season I decided to stop racing. shortly after that decision the motor in my moms 69 chevelle scattered. being the recousefull type, I took the holley 850 headers and aluminum intake off of her motor, and stuck it on the 377 and BAM! mom is on the road again. running super unleaded, it would sometimes ping under full throttle. so a year later I tore it down, ported the junk heads, polished the chambers, polished the piston tops, and stuck it back in. this was 7 or 8 years ago. she commutes 20 miles each way to work. it now runs on 87 octane fuel, and never pings or detonates. it never ever runs hot. the guage shows the same temps as the previous motor. the motor was supposed to just be a loan, but now she will not let it out of her car.
the 400 got a bad rep for overheating back in the 70's when repair shops would stick replacement heads on when a customer got a valve job, they didnt know to drill the steam holes. stock 400 heads are prone to crack around the factory steam holes, and I aviod the factory 400 heads.
I used to avoid 400's, now I swear by them. regardless of configuration, I would not use the factory short rod. you can easily buy a piston that uses the stock 400 crank and a 5.7" rod.

[turbo350]

I had a Weiand street blower on my old 400 with Dart iron heads and was that a fun set-up in my 1/2 ton. I ran a nice aftermarket aluminum radiator and electric fan and never came close to overheating. Same engine is now pushing my uncles 23 foot boat to almost 70 mph with no issues.

[nbpro]

I think the key word here was "thinking" about destroking the engine. All of this is probably a long ways away. Most of my 400 knowledge is from my brother's old GTO back in the late 70's. So I'm having to freshen my memory on things. Just wanted to get some input, which I see I have done. Thanks for all the input guys. keep it comeing

[sasktj]

I used to run "thunder stock" stock cars and after the first couple of years ran a 400. We had to use STOCK GM parts. We were not allowed to do anything with the stroke. I ran a mild cam "RV" and 305 4 barrel heads. We caught a guy cheating who had destroked a 400. I spanked him EVERY weekend. Torque rules

[sasktj]

Pontiac 400 is a different animal then a chev 400

[Allensracing]

Originally Posted by sasktj

I used to run "thunder stock" stock cars and after the first couple of years ran a 400. We had to use STOCK GM parts. We were not allowed to do anything with the stroke. I ran a mild cam "RV" and 305 4 barrel heads. We caught a guy cheating who had destroked a 400. I spanked him EVERY weekend. Torque rules

I agree. I only ran a 377 because we had a 360 CI limit in my class, and they allowed a certain percentage of error. they knew a 383 was too big, but my 377 snuck through the test

[nbpro]

Originally Posted by sasktj

Pontiac 400 is a different animal then a chev 400

yes sir your right so am doing my homr work
The Chevy 400 is a member of the small block chevy engine family and has a great deal of parts interchange with 265-350 chevys. (heads, intakes, distributors, water pumps, exhaust manifolds). The small block chevy 400 has 4.40" bore spacing, a deck height of 9.025 and 2.65" main journals.

The Pontiac 400 is a member of the Pontiac V8 family and has interchangability with Pontiac V8s 287-455. (heads, intakes, waterpumps, distributors, exhaust manifolds). The Pontiac 400 is physically larger with a bore center of 4.62", a deck height of 10.23" and main bearing journals of 3.00".

The two engine families however have almost nothing in common, and almost no parts will interchange. The only thing they do have in common is the both share a 4.12 bore and 3.75 stroke. Pistons, crankshafts, and connecting rods, will NOT interchange due to design parameters. Both engines also require a specific transmission bellhousing since they do not share the same bolt pattern.

[nbpro]

Originally Posted by sasktj

I used to run "thunder stock" stock cars and after the first couple of years ran a 400. We had to use STOCK GM parts. We were not allowed to do anything with the stroke. I ran a mild cam "RV" and 305 4 barrel heads. We caught a guy cheating who had destroked a 400. I spanked him EVERY weekend. Torque rules

You remember what the cating numbers were on those heads? And the valve size? Reason I asked, is I can get a good set of 305 heads. 1.86 and 1.50

[3r!c84]

Dont waste your time with 305 heads lol they flowed like crap on the 305s and will never flow on a 400
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[sasktj]

the 305 4bl just helped to up the compression and flowed better the 400s