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707 HP 402 Build On Youtube

18K views 33 replies 20 participants last post by  Jebchevelle 
#1 ·
#3 ·
On that note...

I was looking at the latest hot rod magazine that features two EMC BBC builds. For some reason, both builders are running 396/402 blocks with < 4.25" bore and using a 4.25" crank to arrive at ~470 c.i. This is the class that required builders to use Edelbrock 100cc heads.
 
#4 ·
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-------OK...... l:)






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#8 ·
I guess you can't believe everything you see posted on the internet I take it.
 
#11 ·
Oh man, I really wanted to see one. I was thinking this will be cool. Then as soon as I saw the numbers posted at the beginning of the video, I was thinking Is this a joke?? And yeah it was.
 
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#14 ·
So I know we don't get the specs of this engine, but what do you people "think" this motor make? I see corrected and uncorrected on the sheet.

402 with 11-1, hyd roller cam???? 702 heads with 219/188 valves with some work, holley 750?

We have for some comparisons:

Joe Sherman's 9.75 to 396 that went 557Hp,

now I made a thread about this one, yet no one seemed to dispute it.
Super Chevy's 396 Build, 10.25 to 1 with a 750 Holley made 577Hp, How to Increase Horsepower -Super Chevy Magazine

Our very own Mark Jone VORTEC PRO L-78396/375 build made 452Hp, http://www.chevelles.com/forums/13-performance/810825-1969-l78-396-375-hp-dyno-test.html

Chris Struab 10 - 1 396 with OEM 702 and hyd roller and 750 made 450+Hp, now there are others in this thread, Vigg, that also had a 396, UNPORTED 702 head, solid roller with 10 - 1 and 750 and made 511Hp http://www.chevelles.com/forums/13-performance/927850-10-1-396-702-gm-heads.html

My old 396. NEVER dyno'ed but ran at the track ONCE in 1/4 to 10.47 @ 3300, and about 15 - 6.40 passes in the 1/8. I figure that was about 550-575 range.

Reason is, I want to do a 600+Hp (601 or better LOL) 396/402 based engine. I would like to use OEM heads and block. I think I'm going to get there and I have heard from both Gary in NY and Mark Jones that BOTH have done it and BOTH have 396/402's that have been over 700, so there is some HOPE.


Mine is as follows:

- 402 short block ('72 4 bolt block built to L-78 specs. , standard bore, GM crank and rods, ARP bolts, TRW 11.5-1's)
- PORTED '69 215 heads, 2.19/1.88, flow right at 325 @ 700
- Holley Strip Dom intake, or 454-O (as per Marks recommendations)
- Bullit SR .710/.710, 264/274 on 106Cl 108 LS
- reworked Holley 830


Now I'm not saying this is one of those REAL 700Hp 396/402's, just wondering what you guys think this made and why from the info we were given. Is it a real 630Hp engine???

DISCUSS[/Q are you talking abought a stock 396 running 6.40s in the 1/8 , tell us your combo
 
#13 ·
I don't pretend to know anything about potential HP for these, but adding %12 for 1,400' elevation sound right? My guestimate would be well under %5, more like %2-%3.
 
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#17 ·
700hp out of a BB? That's nothin' Here's their 900hp 383!

 
#19 ·
thats a hell of a combo, sounds like you hit right in the ball park. some of those short stroke big blocks are high winders , i call them buzz bombs . my friends brother had a 69 nova back in the day it was big block 396 he was shifting that thing a 8000 grand all day long
 
#20 ·
That's a hell of a street engine 900 hp @ 6400. Wonder how they do that????? :secret: l:) l:)
 
#22 ·
well heck I know someone that has a 396 block and stock forged crank at his shop now for some poor fool with no money.lol If said poor boy ever gets the money you might just build a real nice short block out of it to put under a box stock pair of Brodix 270 RR-Ovals with a hydro roller. Will shoot for 650-700 real world HP out of it but we are talking I beam rods and maybe custom pistons, so as light a rotating assembly as we can get and all the tricks you use to make a big CID engine make big numbers. Time and money will determine exactly what happens. thinking 408 CI. 10.5:1 comp, cam is a what ever works best with the heads and the comp ratio. any way just a dream, little more then that right now.
 
#23 · (Edited)
The best NHRA stock eliminator 375 HP 396s make 620 crankshaft HP and get turned around 7800 in the lights, for an example. If seen 9.70s in top stock (all the weight out) @ 3200, 10.28 @ 3780. RPM is key here. I've also seen Holyrod run 135 MPH 9.90 @ 3400 @ Pomona and remember Pomona is a 28.90 baro, but is also down hill.



So forum, whats faster a 408 that makes 620 HP @ 7200 RPM with 520 TQ @ 6000 RPM, OR a 408 that makes 625 HP @ 6600 RPM with A TQ peak of 528 @ 5600 RPM? Interesting to note these engines use a single pattern cam. Example below of a L78 375 HP 396 NHRA stocker.
https://youtu.be/EyksWlC-HFo
 
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#27 ·
what about a 434 version of this engine? or maybe even a 461? car craft did a 4.250 stroke crank and 4.155 bore custom Ross pistons and a 6.385 rod version. there are some interesting things that can be done with custom pistons but then it borders on the should you do it kinda thing. plus the cost to build these combo's can very well out way the return.
 
#32 ·
^^^^ torque would be my guess, the longer stroke should in provide more torque then a 4 inch stroke crank. I know people told me the 3.76 strock 427 makes less torque then a 4.00 stroke 454 given same bore with only a stroke change it is also why some use a 4.25 stroke crank in a stock bore block to give more CI and more torque.
 
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