should I go 350, 383, or 400??

[69GMC910]

I am building an engine for my truck and I have everything decided except for choosing the displacement.


What I have right now for parts are the edelbrock perf. rpm heads, RPM air gap, crane 1.6 roller rockers, comp XE274 cam and misc other goodies.

I would like to be over 400hp with this engine and would like to have respectable 1/4 mile times as well.

Tranny and converter suggestions are also welcome!!

Thanks,
910

[jlmtrout]

Go with the 383 if for no other reason than the greater amount of torque created by the longer stroke. You can use stock length rods, just need pistons for the longer stroke (pin is located lower on the piston skirt). Good luck and keep on truckin'.................Jerry

[rn2fine]

I agree with jlmtrout. 383

Good Luck,

Jeff

[stllookn]

400...displacement and stroke...best of both worlds!

[jlmtrout]

My brother-in-law had a 400 in his 4x4. He complained about "spider-web" cracks in the heads, plus something about "siamesed" ports that he didn't like. If you get after market heads, they will have to have steam holes drilled in them. Plus, good 400 blocks are getting harder to find that are in decent shape. Good luck and keep on truckin'...............Jerry

[Longhorn Man]

400 2 bolt main.

[Tx Firefighter]

400- All the stroke that the 383 has, but even more displacement.

It takes about 5 minutes to drill the steam holes in the heads. Tons of engines have siamesed bores and they run fine. 400 problems are a myth.

[thisolechevy]

turbo 400 tranny to a 400 2-bolt and you'll be running low 11's on the 1/4 mile.

[69GMC910]

I have an guy wanting to sell me his 400 4 bolt short block for $350 CAN. The block is not bored but the crank, rods etc have about 200 000 miles on them. Is it too risky to buy this and hope everything else inside is fine??

The 350 I have (73 Z28 4 Bolt) Has a very strong bottom end with 10:1 flat tops. The engine was rebuilt about 40 000 miles ago. It was basically built to spec of about 245hp, but now I have all these new parts that I'm itchin' to use.

Would anyone here put the all the work into the top end when the bottom end has 40K on it?? Will the bottom end last???

Is anyone here running the XE274 cam, Tell me what you think of it!

Thanks

910

[68w/sbc406]

since you have a 350 that would probably be the way to go, building a 383 would be more expensive than rebuilding that 400, and like said before steam holes only take 5 minutes to drill. so far i love my 400. i got it pretty hot a few times when i was stuck in traffic on 100+ days and no problems. most of the horror stories that people have about 400s the steam holes wernt drilled right or at all on the heads that they put on

[LONGHAIR]

400 and I'm a big fan of the 700r4 trans to go with it. Lower 1st gear and overdrive.....can't beat it.

[69GMC910]

What were the 400sb 4 bolt main 70-72 engines installed in? I assume they were in vans and 3/4 tons

910

[1972Supercheyenne4wd]

400 block 350 crank 6.0 rods. 377 destroke it, tightest rapen sun a gun . you can pull out extreme horse power out of this baby, you might want to invest in scat crank, pop up pistons and all that other good stuff. CROWER BAJA HA Beast cam BABY!!!!!!!!!

[bigjimzlll]

Originally Posted by thisolechevy

turbo 400 tranny to a 400 2-bolt and you'll be running low 11's on the 1/4 mile.

ummmm...may be in a 2500lb ride..in a 4000lb ride low 13s would be respectable with a 400HP 400ci engine, might even squeak into the 12s if all of the planets line up right

[69GMC910]

Yeah, I thought 11's was quite optimistic, I am hoping to run 14 flat or better.

I am planning on running 3.73 with a 28 inch tire, what stall converter do you guy's recommend for the XE274 with this setup? I am planning on removing the original powerglide and dropping in a TH350. The truck is going to be used about 70% cruisin and 30% dragging. I was thinking in the 2800 range but I am not sure if this is too much or too little.

thanks

910

[Blue85]

377 man, wicked power, run all the good stuff on the bottom end cap it with 64cc heads, 10to1 compression she'll freakin rip hard.

[69GMC910]

What is the stroke length of the 377???

[nate68]

you're going to need good aftermarket heads on any high performance motor. I like Dart personally.

[LONGHAIR]

The stroke of a 377 is the same as 350.......3.48"

[neonlarry]

JMO but those heads are a little on the small side (170cc) for a 400. Great for low end but top end will probably fall off some.

[kwmech]

. The truck is going to be used about 70% cruisin and 30% dragging. I was thinking in the 2800 range but I am not sure if this is too much or too little.

thanks

910[/QUOTE]
What is the power band of the cam--also I would figure out how many cubes you want that cam to work with before you order up a convertor. the amount of cubic inches will change the torque band. For example I have used the same cam [crane268] in a 350 and a 400 and got totally different results with power, lope and rpm.

[crazy longhorn]

If you go for a 377 (thought about that hard, as I have a butt load of gears). Go for an aftermarket crank, scat or Eagle should be able to put you into a 3.5 stroke....just a tick longer that a stock 350 crank. She will make a few more cubes(381-382...didnt do the math). the big thing , is thatthe aftermarket crank can be had with the stock 400sb main journal sizing(no bearing spacers. I would build that one with a 6" long rod, & rev it to the moon with my 6 gear trans.....bet it would beat the "toad snot" out of a 383(upstairs). crazyL

[69GMC910]

So lets just say I assemble my 355 with the XE274 cam, 1.6 roller rockers, Performer RPM 64cc heads, RPM Air-Gap Intake , and leave the bottom end the way it is, (10:1 Flat tops). What can I expect this engine to produce??

Also the XE274 is a .490 lift cam, correct me if I'm wrong but with the 1.6 rockers, will my lift actually be .523???

And if so, with this combination should I be worried about piston to valve clearance??

Thanks

910

[bigjimzlll]

if you actually end upwith 10-1 compression, then it should be a nice combo. Add a 2800-3200 stall and it will get up and go. PV clearance should'nt be a problem..but check it anyways..The reason I said if you actually end up with 10-1 is because the head CC's and piston valve reliefs are not always what the box says

[69GMC910]

Yeah the guy at the speed shopsaid it would most likely be around 10.4:1.
bigjimzlll- What have you done to your engine to make your truck so fast, are you running a hyd. roller cam???