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Sbc 400 vs 415 vs 427?

General engine tech -- Drag Racing to Circle Track

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MadmanMark
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Re: Sbc 400 vs 415 vs 427?

Post by MadmanMark » Thu Jan 16, 2020 9:15 am

My brother and I have been running 4" stroke LilMs with 210 AFRs (10.7:1) that were put together about 15 years ago (by FastTimes). Both have over 50k miles on them of mostly street driving. He runs a 300 shot and has been mid-9s in a 3600lbs Camaro and hits the track 1-2 times/year. I've run low 11s in a 4000lbs Chevelle (mid-10s with a 125 shot), but only hit the track about one time each year. The Chevelle has been autocrossed and run on Sebring a bunch. Both cars have survived Hot Rod Power Tours and if I could get my brother conned into caging his Camaro, we'd love to do Drag Week.

Both cars use 248/254 CC HRs with .6/.62 lift. His engine peaked at 630hp/6200rpm (no dyno for mine). I think if we could do it over, we might make similar choices since these cars are both mostly street and get a lot of use. If we were more serious about racing, I think I'd avoid the 4" stroke w/o a raised cam block (only 1" for Piston CH) and look to increase rpm (new heads/cam & maybe pistons?).

econo racer
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Re: Sbc 400 vs 415 vs 427?

Post by econo racer » Thu Jan 16, 2020 9:50 am

I would like to build a 434 or 454 sbc using the stock block kept at 5500 rpm's or less. I am kind of a block and head casting purist. A 454 sbc will pull a open trailer easy.

SpeierRacingHeads
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Re: Sbc 400 vs 415 vs 427?

Post by SpeierRacingHeads » Thu Jan 16, 2020 10:18 am

CPMotorworks Inc of Janesville, Wisconsin built 420ci SBC using SRH VFactor 2.50PF CNC heads. 11:1 CR, 237° @ .050" intake lobe hydraulic roller cam, CPM ported 2925 SV intake, QFT 4150 carb, 1.75" × 3.5" headers. 640hp/585lbs on pump gas and MS109.

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Re: Sbc 400 vs 415 vs 427?

Post by Joe-71 » Thu Jan 16, 2020 11:46 am

And that is 1.52 hp/ci for the 420 ci. Take that number and multiply it against any cubic inch you want to build, and you will have a "ballpark" number to work towards. Joe-71
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Mikej26
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Re: Sbc 400 vs 415 vs 427?

Post by Mikej26 » Thu Jan 16, 2020 11:15 pm

SpeierRacingHeads wrote:
Thu Jan 16, 2020 10:18 am
CPMotorworks Inc of Janesville, Wisconsin built 420ci SBC using SRH VFactor 2.50PF CNC heads. 11:1 CR, 237° @ .050" intake lobe hydraulic roller cam, CPM ported 2925 SV intake, QFT 4150 carb, 1.75" × 3.5" headers. 640hp/585lbs on pump gas and MS109.

Chad, when I get around to stepping up the breathing capacity I will be coming your way for a set of these heads.

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Re: Sbc 400 vs 415 vs 427?

Post by SBC-68-FIREBIRD » Sun Jan 26, 2020 2:12 am

This may be of some interest to you.
I have a 68 Firebird full weight street car - 3620lbs with me in it. It is 90% street but does go to the track 2-3 times a year.
3.73 gears.
275/50/15 MT drag radials.
T400.

I had an old 406 SBC that was built back in the late 90's, swapped the heads, cam & intake.
406 bottom end, GM crank, 5.7 Eagle Rods, TRW flat tops, 10.7 comp, street port AFR195's untouched, 242/248@50 Hydraulic roller, Super Victor, 830DP, 1.75" press bent headers into dual 3" dumped in front of the diff. Never went on an engine dyno but got the car down to 11.08@122mph with a 9.5" 4000rpm converter.
Had that engine for a long time & gradually collected gear for a new engine, just as a refresh.

New engine -
Dart Little M, 4.155 bore, 3.875" stroke so 421 cubes. AFR 210 competition port heads untouched, 11.7 comp, 246/250@50 Hydraulic roller, Super Victor match ported to heads & plenum ported, 850QFT carby. Same headers.
Made 580HP@ 6000rpm & 550TQ @ 5000rpm with shop headers. Ran it first up with the 830 which was an old modified annular. Made 550 as the carby was so put the QFT on it.
Put the engine in the car & it ran exactly the same times & mph but did not like the converter so I had it modified to 5000 stall but it was not nice on the street so I changed converters again to an 8" 5000 converter, much nicer on the street. Has since gone 10.8@122.
Feels like the top end of the track its just cruising down there so have just put a set of 1 7/8" mandrel pipes on it with 3.5" collectors. Am yet to run it at the track.

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Re: Sbc 400 vs 415 vs 427?

Post by mtrhead » Sun Jan 26, 2020 9:34 am

Why not use the 5.850 rods? Available and provide more cam clearance. Use a 1.25 c/h piston and let piston come out of hole .012” or use custom pistons, or just use a slightly shorter stroke crank if you don’t like a slightly positive deck.
When buying a new crank custom work that doesn’t cost much more. If you called a place like Callies they’d hook you up with right crank for not much more than standard.

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