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400 SBC build

General engine tech -- Drag Racing to Circle Track

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Monza355
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Re: 400 SBC build

Post by Monza355 » 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

tcb3274
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Re: 400 SBC build

Post by tcb3274 » Tue Jun 23, 2020 7:10 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
Yes, I agree. Just trying to make sure I can get as much as I can with a one time selection of parts.

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Re: 400 SBC build

Post by F-BIRD'88 » Tue Jun 23, 2020 7:50 am

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.

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Re: 400 SBC build

Post by rfoll » 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.
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So much to do, so little time...

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Re: 400 SBC build

Post by Monza355 » Tue Jun 23, 2020 1:00 pm

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 ?

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Re: 400 SBC build

Post by rfoll » Tue Jun 23, 2020 7:58 pm

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.
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tcb3274
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Re: 400 SBC build

Post by tcb3274 » 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?

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Re: 400 SBC build

Post by rfoll » 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.
So much to do, so little time...

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Re: 400 SBC build

Post by Old School » 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.

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Re: 400 SBC build

Post by rfoll » Wed Jun 24, 2020 1:07 pm

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.
So much to do, so little time...

tcb3274
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Re: 400 SBC build

Post by tcb3274 » Wed Jun 24, 2020 1:38 pm

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.

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Re: 400 SBC build

Post by rfoll » Wed Jun 24, 2020 3:36 pm

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.
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tcb3274
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Re: 400 SBC build

Post by tcb3274 » Thu Jun 25, 2020 8:37 am

Any other comments?

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Re: 400 SBC build

Post by 1980RS » 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.

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Re: 400 SBC build

Post by tcb3274 » Thu Jun 25, 2020 12:14 pm

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.

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