Thread: Tell me about a 400 sb

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I like long headers for daily drivers. I don't think shortys will do much for you except at high rpms.

I ran a couple of 400's in stock cars 20 some years ago. Great engines, lots of cheap horsepower. They were tougher to keep cool than a 350 in that application, and they were less forgiving of high RPM's due to the longer stroke. I saw plenty of them get blown up with guys running stock bottom ends at 7000 plus RPM.

If I found one with 80,000 miles for $650, I would jump on it.

Originally Posted by firebird77clone

I like long headers for daily drivers. I don't think shortys will do much for you except at high rpms.

That's I was hoping to hear, it's going to save me a quite a bit in exhaust, if it doesn't help much it's not worth it for this app.

Originally Posted by Driver50x

I ran a couple of 400's in stock cars 20 some years ago. Great engines, lots of cheap horsepower. They were tougher to keep cool than a 350 in that application, and they were less forgiving of high RPM's due to the longer stroke. I saw plenty of them get blown up with guys running stock bottom ends at 7000 plus RPM.

If I found one with 80,000 miles for $650, I would jump on it.

I really thought about it because it would be a direct bolt in, but according to specs it's no power house the way it sits. It'll need heads, cam and an intake to make it decent then the 80k mile thing really isn't worth it to me. It doesn't cost too much to build a bottom end. I think I'll be able to leave the 350 together because the heads are great and just swap the cam.

Maybe instead of some used junk yard engine you ought to look at the Dart SHP line--and put some decent aftermarket heads on it with 2.080 intakes, 1.650 exhaust, rollers, jesel type rocker system ( maybe on canted valve heads?)-

lots of options with those blocks-stroker clearance, wide pan rails,rasised cams, bigger cam bearings including roller needles----------

Maybe instead of some used junk yard engine you ought to look at the Dart SHP line

I prefer the term -Pre Owned I'm saving the cash for the 71. I'm just trying to liven the Z28 up while holding to a budget on it. I have heard both the motors I talked about running so it's not a complete crap shoot.

hearing them run doesn't say much about the end cost of a project------you don't know anything about cylinder bores, rings,pistons, bearings, etc,etc---figure out what you want in the end---------but do first look at all possibilties of how to get there-------

That's the whole problem with this car my mind goes from full blown 383 stroker to just warm the 305 as much as I can while still leaving the heads on. I figured camming a 350 that already has good heads on for decent power would be a good middle-of-the-road option.

Get the 400---make him reduce the price to cover a new set of bearings and pan gaskets

Pull a head and measure the bore. You want a standard bore block (4.125). If it has already been overbored, it's pretty much junk.

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You guys are hard on someone who is self diagnosed with ADD. Ok, lets pretend the 400 bore is in perfect shape and I leave the factory heads on and swap intake and cam. What kind of motor am I going to end up with power wise and fuel wise vs the Vortec with better heads and a cam swap. It may be getting to be a 6 to one 1/2 a dozen to another. I feel kinda dumb asking these things but to be honest, I've been more of a tractor mech all my life. I've assembled a fair amount of Chevys and Fords but I didn't have the know how to pic all the parts that worked together . I left that part to others that know better.

i will be finding out myself how a 400 does. Found a complete 509 block one with a th350 on it at a flea market type place in perry kansas for 700 dollars. Had a freind rebuild the transmission (2500 rpm converter) then we rebuilt the stock bottom end put a mild cam with 487x heads(drilled steam holes) an performer intake with a 3310 holley up top. hope it will be a fun driver.

on a budget i have tore down, cleaned and put new bearings and gaskets in one. lap the valves . i used a 262 cam for street . kit has new gears/springs . performer rpm intake and 600 holley . low budget motor but i never had a failure .

Originally Posted by partchucker

i will be finding out myself how a 400 does. Found a complete 509 block one with a th350 on it at a flea market type place in perry kansas for 700 dollars. Had a freind rebuild the transmission (2500 rpm converter) then we rebuilt the stock bottom end put a mild cam with 487x heads(drilled steam holes) an performer intake with a 3310 holley up top. hope it will be a fun driver.

What's the static compression ratio? What cam did you use? What's the squish/quench?

Trade off the Performer for a Performer RPM #7101 or a Weiand 8150 or a used Holley 300-36 or a used Weiand 8014. You're gonna leave 30-40 hp on the table with that short intake manifold and the motor will have all the bottom end you can handle with the taller intake (power from 1500-6000) and 2500 converter.
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