yep the best thing to do with a 400 is but a set of 6" rods, and for all the cooling concerns.......they are BS My Stepside is .040 over with a 3-core Rad, A/C and driven in New Mexico desert heat never ever ever had any sort off cooling problems
CK5
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which is the greater evil?
- Thread starter mudbuggy
- Start date
The only time I have had a 400 get hot was in my Dad's '72. He got it stuck climing a hill, chained up in the mud at 9500ft elevation. It worked the TH400 a bit getting out with his 3:08 gears so engine and trans making a fair amount of heat. Keep in mind that if the tune isn't right, alot of engines will get hot. I have seen guys cuss their engine for that and found the ignition timing late causing a large part of it.
COCHEV
1/2 ton status
With the goals you have for the motor, wouldn't a 454 make good sense? With all the gas guzzlers on the chopping block, you could get a doner motor, if not the whole damn truck pretty cheap. 
I loved the torque in my old sbsb400, but after have a 454, I'd pick the big block. Just my. 02
But if big blocks are not a option I vote sb400
I loved the torque in my old sbsb400, but after have a 454, I'd pick the big block. Just my. 02
But if big blocks are not a option I vote sb400
mudbuggy
1/2 ton status
Reply by blackberry- I found an old timer that is handicapped now that was big in 400s in the late 70s. He is selling me 3 400 virgin blocks (509 castings) for $200. How he tells me is that he had a buddy at GM that was qc for the 400 casting line. More then half of all production got 'rejected'. The old timer that I know, had a contract with the casting division to destroy and cast billet slugs (1000 lb) and deliver back to the plant where he picked up the 'rejected' blocks.
I have seen a picture of the old timer's son at his 40th birthday wirth his father's presents to him. A baker's dozen (13) 509 casting 400 blocks!
If I had a 'deal on a 454 I might go that route, but sadly I must deal with the cards that I jave been dealt (looks like three of a kind) lol. Most of the time Murphy is tap dancing on my skull, right now I am dancing a jig, at least for the moment!
I have seen a picture of the old timer's son at his 40th birthday wirth his father's presents to him. A baker's dozen (13) 509 casting 400 blocks!
If I had a 'deal on a 454 I might go that route, but sadly I must deal with the cards that I jave been dealt (looks like three of a kind) lol. Most of the time Murphy is tap dancing on my skull, right now I am dancing a jig, at least for the moment!
Pookster
1/2 ton status
reliability
I have no experience with the motor. But I will say this- Even nevada/new mexico heat doesnt exceed 140 degrees. So you still get a 40-50 degree temp differential. If a motor runs hot, it runs hot. Its pure and simple.
Just how many therms can air flowing past the radiator remove?
Its not as many as you would think, without the vehicle in motion. You don't need a fan when the car is in motion. You need a fan when the car isnt moving.
You can literally calculate the therms of heat produced by the motor, and the therms of heat that the radiator can dissipate, given the amount of air movement of the fan.
Add on caked mud, dirt, etc, oil coolers, trans coolers...the actual effective cooling is severely diminished. Deep in the forests out east, there isn't even a stiff breeze. Underhood temps are ridiculously high- manifolds, engine, hot air from the radiator, beaming sun..
And I kinda like to run AC.
Now.. If I were doing a swap, I might consider an ecotec LNF motor, with the remap. 290HP, 340ft lbs of torque. I think its less than half the weight of a SBC. Its intriguing. But Probably not as cost effective as a LSx motor of some sort.
I have no experience with the motor. But I will say this- Even nevada/new mexico heat doesnt exceed 140 degrees. So you still get a 40-50 degree temp differential. If a motor runs hot, it runs hot. Its pure and simple.
Just how many therms can air flowing past the radiator remove?
Its not as many as you would think, without the vehicle in motion. You don't need a fan when the car is in motion. You need a fan when the car isnt moving.
You can literally calculate the therms of heat produced by the motor, and the therms of heat that the radiator can dissipate, given the amount of air movement of the fan.
Add on caked mud, dirt, etc, oil coolers, trans coolers...the actual effective cooling is severely diminished. Deep in the forests out east, there isn't even a stiff breeze. Underhood temps are ridiculously high- manifolds, engine, hot air from the radiator, beaming sun..
And I kinda like to run AC.
Now.. If I were doing a swap, I might consider an ecotec LNF motor, with the remap. 290HP, 340ft lbs of torque. I think its less than half the weight of a SBC. Its intriguing. But Probably not as cost effective as a LSx motor of some sort.
