Thread: 357 Magnum

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Question; if we go with a 421 vs the current 357, would the truck be any faster?
Currently my son has a 357 sbc in a S-10 extended cab which weighs 3800 lbs. We have 10.5;1 compression with Vic. Jr. heads which have been flowed to 300 cfm intake and 225 ex. We have a solid roller cam and roller rockers. The cam has .582 and .588 lift with 1.5 rockers but we have 1.6 and duration at .050 is 254 and 260. ( http://www.compcams.com/Technical/Se...umber=12-773-8 ) A Vic. Jr. intake port matched and a new Holley 780 Vac. sec. The tranny is a 700 R 4 and ford nine inch with 456 gears. MT ET’s are 26 inch by 10.5. The tires do not hook really well so the best we can get on the 60 foot is a 1.8x

His best N/A was a 12.9 @ 111 mph with his old carb, a 700 Holley. We haven’t had it to the track with the new carb but it runs a whole lot better with it. We thought it should have hit low 12's with the current set up.

Originally Posted by TyphoonZR

Question; if we go with a 421 vs the current 357, would the truck be any faster?
Currently my son has a 357 sbc in a S-10 extended cab which weighs 3800 lbs. We have 10.5;1 compression with Vic. Jr. heads which have been flowed to 300 cfm intake and 225 ex. We have a solid roller cam and roller rockers. The cam has .582 and .588 lift with 1.5 rockers but we have 1.6 and duration at .050 is 254 and 260. ( http://www.compcams.com/Technical/Se...umber=12-773-8 ) A Vic. Jr. intake port matched and a new Holley 780 Vac. sec. The tranny is a 700 R 4 and ford nine inch with 456 gears. MT ET’s are 26 inch by 10.5. The tires do not hook really well so the best we can get on the 60 foot is a 1.8x

His best N/A was a 12.9 @ 111 mph with his old carb, a 700 Holley. We haven’t had it to the track with the new carb but it runs a whole lot better with it. We thought it should have hit low 12's with the current set up.

i don't think 12's is to bad for that motor. what rpm's are you turning at the line?

Originally Posted by lt1s10

i don't think 12's is to bad for that motor. what rpm's are you turning at the line?

I was hoping you wouldn't ask that because we have a small problem with the tranny not wanting to shift at WOT so he has to let off for a second or two till it shifts. But it is over 7000 rpm. One thing I forgot to mention is that he has a 3000 stall converter.
He made one run with nitrous and got confused with his shifter and so he put it in neutral. He thought he was going for O/D but forgot that he had already placed the shifter in second when he did the burn out and forgot to bring it back into first. He hit neutral at the 1000 ft mark so he just coasted through at 110 mph in 11.4 seconds.

The 421 will make more power and will run faster no doubt especially with the Vic Jr heads.

I see a lot of potential for the current setup though with tuning and traction. All the power in the world will do no good if it can't be put to the ground. Taller tires will hook better due to the sidewalls. Work on the 60ft. You got enough MPH for 12.0's at least.

If you want to build another engine, instead of going to the 420, go with a 412cid. That is a 3.8 stroke crank and 4.155 bore size. The heads you have will fit that combo well.

Originally Posted by camaro_fever68

The 421 will make more power and will run faster no doubt especially with the Vic Jr heads.

I thought so too. I had those heads (my son got the hand me downs) before all the port work and I ran 11.78 @ 111 with my ride and a 406 but my truck is 400 lbs lighter.

Originally Posted by camaro_fever68

I see a lot of potential for the current setup though with tuning and traction. Taller tires will hook better due to the sidewalls.

Agreed, next season, bigger tires. He's got the gears and converter to handle it.

Originally Posted by camaro_fever68

.... go with a 412cid. That is a 3.8 stroke crank and 4.155 bore size. The heads you have will fit that combo well.

Why not a 420/421? Too big a stroke?

Originally Posted by TyphoonZR

Why not a 420/421? Too big a stroke?

420+cid will be head limited with anything under 227cc runners. Not a bad thing if you're using a GM 400 block though. I figured a 6500rpm redline and that would be a perfect combo of parts on a 410/412 short block. You could back down on the gear and go with more tire though and use the torque of a 421cid to pull it. You'll most likely run out of head by 6000rpm.

Originally Posted by camaro_fever68

420+cid will be head limited with anything under 227cc runners. Not a bad thing if you're using a GM 400 block though. I figured a 6500rpm redline and that would be a perfect combo of parts on a 410/412 short block. You could back down on the gear and go with more tire though and use the torque of a 421cid to pull it. You'll most likely run out of head by 6000rpm.

Good call Ray.
I would also say a fully CNC'D 23 degree head will support up to 650 hp in a natually aspirated engine after that I would be shopping for a set of 18 degree heads.

Originally Posted by camaro_fever68

You'll most likely run out of head ....

Well,.... we wouldn't want that, would we? Thanks for the heads up!

Originally Posted by TyphoonZR

Well,.... we wouldn't want that, would we? Thanks for the heads up!

Oh,I know.
Pull your head out.
Do you like it up there??
Yes,I was kidding.
Do you think that was to much??