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Re: 400 SBC build
Posted: Tue Jun 23, 2020 7:07 am
by Monza355
Even though it’s tempting I wouldn’t aim for a specific hp number. For a street car it doesn’t matter if it’s 450 or 500 hp. I would aim for a mild mannered engine with broad Powerband. You should still be able to make burnouts for distance
Re: 400 SBC build
Posted: Tue Jun 23, 2020 7:10 am
by tcb3274
Monza355 wrote: ↑Tue Jun 23, 2020 7:07 am
Even though it’s tempting I wouldn’t aim for a specific hp number. For a street car it doesn’t matter if it’s 450 or 500 hp. I would aim for a mild mannered engine with broad Powerband. You should still be able to make burnouts for distance
Yes, I agree. Just trying to make sure I can get as much as I can with a one time selection of parts.
Re: 400 SBC build
Posted: Tue Jun 23, 2020 7:50 am
by F-BIRD'88
Yes I recomend solid flat tappet cams to get a real deal 500 hp on your 400 sbc.. Those 2 hydraulics are in the ball park.
Of the comp XE284H-10 hyd cam
A example of a "big dual plane" is The Performer RPM Hi rise and like... Dart Holley Typhoon etc.
The typical sbc single planes make a bit more top end hp. The good dual plane high rises make more midrange torque overall.
Re: 400 SBC build
Posted: Tue Jun 23, 2020 10:04 am
by rfoll
Monza355 wrote: ↑Tue Jun 23, 2020 7:07 am
Even though it’s tempting I wouldn’t aim for a specific hp number. For a street car it doesn’t matter if it’s 450 or 500 hp. I would aim for a mild mannered engine with broad Powerband. You should still be able to make burnouts for distance
I agree with this completely. My 9.7:1 406 with iron 034 Bowtie heads would boil the tires at 60 mph in high gear. The car ran 11.50s.
Re: 400 SBC build
Posted: Tue Jun 23, 2020 1:00 pm
by Monza355
rfoll wrote: ↑Tue Jun 23, 2020 10:04 am
Monza355 wrote: ↑Tue Jun 23, 2020 7:07 am
Even though it’s tempting I wouldn’t aim for a specific hp number. For a street car it doesn’t matter if it’s 450 or 500 hp. I would aim for a mild mannered engine with broad Powerband. You should still be able to make burnouts for distance
I agree with this completely. My 9.7:1 406 with iron 034 Bowtie heads would boil the tires at 60 mph in high gear. The car ran 11.50s.
Awesome, Great looking street machine !
What was the rest of the combo ?
Re: 400 SBC build
Posted: Tue Jun 23, 2020 7:58 pm
by rfoll
The car is a 78 Skylark. The cam was hydraulic flat tappet 444/444/106,.525 lift. Performer RPM air gap with a 780 vac secondary Holley. 3.73 gears, slapper bars, 3000 converter. T350, 10x26 Hoosiers.1.625 headers and a full 3"exhaust with mufflers. I have cold air to the carburetor, It really is worth the effort. The car weighs 3500 with me in it. Currently with a pump gas freindly 10.3:1 415 sbc, it runs 10.90s/122 mph. You would be amazed at how much more it cost for the next 0.6 seconds. It still has a license, but these days street driving involves going to the gas station and heat cycling everything. A 5000 rpm spragless converter changes the street behavior enough to be a nuisance, other than really long burnouts for the cruise-in crowd.
Re: 400 SBC build
Posted: Wed Jun 24, 2020 11:47 am
by tcb3274
Well, Im down to three cams. Not sure how they are going to work out with my 10.5 compression, but here they are.
All are flat tappets.
Mike Jones cam - 284/288 and 228/230 @ .050 for .528/.528 lift on 1.6 rockers and 110 lsa
It appears this cam will be around 195 to 210 psi cranking compression on a guess.
Luanti cam - 285/285 and 235/235 @ .050 for .537/.537 lift on 1.6 rockers and 108 lsa.
It appears this cam with its 108 will put cylinder pressure higher around 210 psi to 220 psi on a guess.
Luanti cam - 284/292 and 241/249 @ .050 for .525/546 lift on 1.5 rockers and 110 lsa
It appears this cam will be around 210 to 215 psi on a guess.
*** All these cams overlaps are with in 3.
We could retard the cams some to help bleed off more pressure. To me 220 is about all I want to see for a 93 octane pump gas motor. Others say for a street car, they would like it at 180 or 195 psi. I like the 195 to 200 area myself.
Now if these guesses are based on a 64 cc head. If I got to a 70 cc head, the compression comes down a half a point.
The quench on these build will be right at .040 and it will have a good solid tune and cooling system. The cooling is a 4 core aluminum rad with 2500 cfm fans.
Anybody have thoughts?
Re: 400 SBC build
Posted: Wed Jun 24, 2020 12:31 pm
by rfoll
All of those cams will be fine at 1/2 point less compression. The 1/2 point difference might show up at the drag strip, but for a street vehicle it would seem like cheap insurance.
Re: 400 SBC build
Posted: Wed Jun 24, 2020 12:40 pm
by Old School
tcb3274 wrote: ↑Wed Jun 24, 2020 11:47 am
Well, Im down to three cams. Not sure how they are going to work out with my 10.5 compression, but here they are.
All are flat tappets.
Mike Jones cam - 284/288 and 228/230 @ .050 for .528/.528 lift on 1.6 rockers and 110 lsa
It appears this cam will be around 195 to 210 psi cranking compression on a guess.
Luanti cam - 285/285 and 235/235 @ .050 for .537/.537 lift on 1.6 rockers and 108 lsa.
It appears this cam with its 108 will put cylinder pressure higher around 210 psi to 220 psi on a guess.
Luanti cam - 284/292 and 241/249 @ .050 for .525/546 lift on 1.5 rockers and 110 lsa
It appears this cam will be around 210 to 215 psi on a guess.
*** All these cams overlaps are with in 3.
We could retard the cams some to help bleed off more pressure. To me 220 is about all I want to see for a 93 octane pump gas motor. Others say for a street car, they would like it at 180 or 195 psi. I like the 195 to 200 area myself.
Now if these guesses are based on a 64 cc head. If I got to a 70 cc head, the compression comes down a half a point.
The quench on these build will be right at .040 and it will have a good solid tune and cooling system. The cooling is a 4 core aluminum rad with 2500 cfm fans.
Anybody have thoughts?
It really doesn't matter. They will all run within a tenth or less of each other. If I had to pick one it would be the 235 Lunati on 108.
Re: 400 SBC build
Posted: Wed Jun 24, 2020 1:07 pm
by rfoll
Old School wrote: ↑Wed Jun 24, 2020 12:40 pm
tcb3274 wrote: ↑Wed Jun 24, 2020 11:47 am
Well, Im down to three cams. Not sure how they are going to work out with my 10.5 compression, but here they are.
All are flat tappets.
Mike Jones cam - 284/288 and 228/230 @ .050 for .528/.528 lift on 1.6 rockers and 110 lsa
It appears this cam will be around 195 to 210 psi cranking compression on a guess.
Luanti cam - 285/285 and 235/235 @ .050 for .537/.537 lift on 1.6 rockers and 108 lsa.
It appears this cam with its 108 will put cylinder pressure higher around 210 psi to 220 psi on a guess.
Luanti cam - 284/292 and 241/249 @ .050 for .525/546 lift on 1.5 rockers and 110 lsa
It appears this cam will be around 210 to 215 psi on a guess.
*** All these cams overlaps are with in 3.
We could retard the cams some to help bleed off more pressure. To me 220 is about all I want to see for a 93 octane pump gas motor. Others say for a street car, they would like it at 180 or 195 psi. I like the 195 to 200 area myself.
Now if these guesses are based on a 64 cc head. If I got to a 70 cc head, the compression comes down a half a point.
The quench on these build will be right at .040 and it will have a good solid tune and cooling system. The cooling is a 4 core aluminum rad with 2500 cfm fans.
Anybody have thoughts?
It really doesn't matter. They will all run within a tenth or less of each other. If I had to pick one it would be the 235 Lunati on 108.
I agree with this cam choice.
Re: 400 SBC build
Posted: Wed Jun 24, 2020 1:38 pm
by tcb3274
rfoll wrote: ↑Wed Jun 24, 2020 12:31 pm
All of those cams will be fine at 1/2 point less compression. The 1/2 point difference might show up at the drag strip, but for a street vehicle it would seem like cheap insurance.
I understand the reason to take out 1/2 point of compression.
However I fell like that is to much, maybe settle on 10.3.
Just seems like taking out a full half point it would be soggy.
Re: 400 SBC build
Posted: Wed Jun 24, 2020 3:36 pm
by rfoll
It won't be soggy with the cams you listed. They are small enough to be stump pullers right off idle. A cam that would be nasty in a 350 will be somewhat mild in a 400.
Re: 400 SBC build
Posted: Thu Jun 25, 2020 8:37 am
by tcb3274
Any other comments?
Re: 400 SBC build
Posted: Thu Jun 25, 2020 11:52 am
by 1980RS
tcb3274 wrote: ↑Thu Jun 25, 2020 8:37 am
Any other comments?
My 406 with Stock 906 Vortec's went the best of 11.49 last night with the Elgin 1165P hyd cam.
Re: 400 SBC build
Posted: Thu Jun 25, 2020 12:14 pm
by tcb3274
1980RS wrote: ↑Thu Jun 25, 2020 11:52 am
tcb3274 wrote: ↑Thu Jun 25, 2020 8:37 am
Any other comments?
My 406 with Stock 906 Vortec's went the best of 11.49 last night with the Elgin 1165P hyd cam.
Impressive, not a drag car though.