How fast can a 400 spin?

[riffman]

so im gathering info about building this 400 for mud racing, and i can't seem to find any info on the peak rpm of thsi 400. so how cast can i spin it before it eats itself? gonna be sprayin it with about 12:1 compression with stock heads worked over, forged crank, a little bit, good pistons, and good rods too. so what do ya guys think? will it hit 7000 safely?? I dunno just a number i threw out. any ideas??

[txs]

We are talking about a dodge here and not a 400 modified, right? The stock 346, 902, 452 head castings on a 400 will quit gaining flow at about 5000 or 5400 rpm so you really need to have someone who knows how work the heads hard to keep them pulling to 7000 rpm. If your buying manley (or other good aftermarket) rods and good forged pistons and a good balance job it would probably live at 7000. I would be more comfortable rev limiting to about 6500. Have you considered 440 crank in the 400 block, it makes a killer combo, very light bob weight for a BB, gobs of torque.

[mjs408]

i had my thermo-quad stick open in a muddy trail (butterflys wedged open because of worn out bushings on baseplate of carb, and had my tired stock 360 bounce of a 6800 rev limiter, it scared the piss out of me but it survived several seconds of ultra high reving before i got it shut down, you should have heard the thing diesel, not fun, and even less fun getting it home, i know this really didnt help, your question just made me remeber the full feeling i had in my drawers when i finally got it stopped

[riffman]

Originally posted by mjs408
i had my thermo-quad stick open in a muddy trail (butterflys wedged open because of worn out bushings on baseplate of carb, and had my tired stock 360 bounce of a 6800 rev limiter, it scared the piss out of me but it survived several seconds of ultra high reving before i got it shut down, you should have heard the thing diesel, not fun, and even less fun getting it home, i know this really didnt help, your question just made me remeber the full feeling i had in my drawers when i finally got it stopped

hahahahahahahaha....only got close to that once. and it was actually just the other day..i was driving my dually (16v cummins turbo diesel) and i down shifted, when i though it was going slower than i actually was. BBBBBBBBBBBRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR R....man, did that sucker shoot up in rpm's!! i thought i was gonna blow it up...i mean the redline is at 3000 rpm, but this sucker was up at 4500...i was like EEK! but she held up, and is still running!! god bless cummins!!

[riffman]

Originally posted by txs
We are talking about a dodge here and not a 400 modified, right? The stock 346, 902, 452 head castings on a 400 will quit gaining flow at about 5000 or 5400 rpm so you really need to have someone who knows how work the heads hard to keep them pulling to 7000 rpm. If your buying manley (or other good aftermarket) rods and good forged pistons and a good balance job it would probably live at 7000. I would be more comfortable rev limiting to about 6500. Have you considered 440 crank in the 400 block, it makes a killer combo, very light bob weight for a BB, gobs of torque.

yeah...were talkin about a mopar 400. ya know..it has been rebuilt already for a street vehicle, so i might be better off selling it for a few bucks, then going to a 440 anyway, wouldn't i? do you think that would be a better idea? or even better...know where i can find a cheap hemi??? hehehe

[Lloyd]

Originally posted by riffman


a cheap hemi??? hehehe

Now THERE's an oxymoron. I know where there are several Hemi's, but cheap? Well, that means different things to different people, so you decide. Six-Pack Performance, (505) 345-8539.
A friend of my dad's had bought a NEW 1969-1/2 Charger R/T, 440 6-pack. He was going down the Grapevine when the throttle return spring broke; just suddenly it jumped into and then blew out of second, and was between 6500 and 7000 rpm in 3rd by the time he got the key turned off. Bought four throttle return springs; put two on it, and two in the glove compartment.