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600 HP 396/402 How do we get there?

77K views 49 replies 32 participants last post by  427L88 
#1 ·
Hi there, I'm planning to build my '65 chevelle race only. It will be a built 12 bolt with 4:10 gears and a spool, a built Powerglide etc. I'm planning on running in the low 10's at about 130 mp. I'm guessing the car would weigh in around 3500 Lbs and I would probably handle 28 x 10 x 15 inch slicks. Question is it realistic to reach 600HP with 396/402 CI ? I have several of these 2 bolt blocks and 820 open and 290 closed heads. Also have steel crankshaft, 396/375 trw pistons on factory truck rods, so I suppose I'll run under 6500 rpm. Also have performer rpm and a victor with oval ports. I could use some help sorting thru this and any suggestions on cams and just in general, Thanks Gerard396
 
#2 ·
Let me state the obvious first, it would be easier with more inches. That being said it can be done, but it won't be easy. I would say, it will take a solid roller cam setup. If you are set on using what you have, the rods are 7/16 bolt rods right? The next question is pistons. It is going to take a better piston than the TRW's. I would suggest a lightweight race type piston from J&E or a Wiseco. This will allow you to get the compression as high as practical, 12-1 probably. Then from here you can pick which head to use, I would rather use an open chamber head. I don't think the 6500 rpm limit is practical. This engine will need to go to 7500 to make power. A steel crank, lightweight piston and 7/16 rod will handle this without a problem. On the other hand, you need to look at price compared to performance. Machine work is not cheap, so it may be more cost effective to go aftermarket than recondition stock parts. What I mean is, a set of Eagle or Scat rods, may not be much more than magnafluxing, resizing, and rod bolt replacement of your stockers. Second a set of small port aluminum heads may be a better option than rebuilding the heads you have now. And you can sell what you have and recoup some of the cost. But I can say, my 408 at 10.5-1 with a .574/.588 flat tappet cam, 781 casting heads made 500 hp on 93 octane gas. So it can be done, you just need to look at cost compared to power.
 
#3 ·
600HP from a 396/402, that 1.5 HP/cu in. For comparison there's a bunch of 540s out at around 750HP, that's 1.38 HP/cu in. Those engines have AFR heads, aggressive lobe profile solid roller cams, big carbs on big manifolds, etc. I think you need to fall back and regroup on your HP expectation. You'll be doing well to get 500-525 real HP out of your iron head 402. At that, you might need another 1000RPM on that 6500. Sort of a different ballpark.
 
#7 ·
You'd be better off selling all your blocks, rods, cranks, buy a 454 block, 4.25 crank...


but if your stuck on the 396 gonna need a lot of compression (13:1 or better) big solid roller, and spin it to the moon. Gonna need more gear than a 4.10 to have success with the glide, you'd be better off with a th400/350.
 
#8 ·
Hi Guys, thanks for the reply. I have nothing set in stone at this point and I'm open to suggestions. I have no interest in nos, my concept would be naturally aspirated and 1.5 HP per cubic inch which I know has been done with small blocks. I came up with 600HP ( actually 550-600hp) while using a performance calculator. Could I spin a 2 bolt main big block to 7500 RPM with lightweight pistons and aftermarket 7/16 rods without blowing myself up? I had thought about your suggestions of aftermarket heads and Roller Cams and recycling parts to get to where I want to go. I really would like to explore the smaller big block so I was wondering if anyone had done it. I would hate to do the build-up and fall short. Thanks Gerard396
 
#9 ·
Normally asperated goodluck unless your expecting to build an all out race motor but with spray or a blower its possible but still kinda radical for street.

Scott
 
#11 ·
It can be done but unless you are CI limited why only 402 CI? You could make 650~700HP with less effort with a 468~505. Custom pistons 11.5~13.5:1 light weight H beam rods, angle milled worked over 781/049's flowing 330 cfm. Ported RPM, 250's @.050'' .700'' sld RR should get you there.
 
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#14 ·
Hi there, I'm planning to build my '65 chevelle race only. It will be a built 12 bolt with 4:10 gears and a spool, a built Powerglide etc. I'm planning on running in the low 10's at about 130 mp. I'm guessing the car would weigh in around 3500 Lbs and I would probably handle 28 x 10 x 15 inch slicks. Question is it realistic to reach 600HP with 396/402 CI ? I have several of these 2 bolt blocks and 820 open and 290 closed heads. Also have steel crankshaft, 396/375 trw pistons on factory truck rods, so I suppose I'll run under 6500 rpm. Also have performer rpm and a victor with oval ports. I could use some help sorting thru this and any suggestions on cams and just in general, Thanks Gerard396
First of all i know it can be done and we will be building one later this summer BUT everybody knows i will run the living crap out of it

My street 327 if i had to guess is 540-550hp+ but that engine has to spin 8200rpm, 6100rpm stall and transbrake and all

Could i make the same hp with a larger engine, yes. So i understand you wanting to use the smaller engine

My main question is this,, Will you be building it your self or having it built ?

If your having it built its gonna cost you alot, if your building it you can go off peoples advice

As to the weight, light pistons then send them out and have them lightened more, rods buy light but strong, polish crank to a mirror finish, have good porter port your heads, solid roller cam, spring pressure, premium heavy wall pushrods, titanium retainers etc etc etc (those are the kinds of things you will need)

Maybe you should do some research on an NHRA 396 stocker,, they will push Nova's to 10.60's
 
#17 ·
This sounds like a really cool project. I've wanted to do something like this for awhile. I don't think 600 hp is asking to much. Plus I think you can do it with factory heads. Our 496 with a set of 049 ovals made 730hp with 11.68 to 1 which is 1.47 hp per cube, so 1.5 per cube out of a 396 vary doable. You'll need to make peak power around 7400 rpm.

Here's what I would build

396 2 blot block arp studs
12-1 piston 1.2 , 1.2, 3mm ring pack
Closed chamber oval ports. The last set I did flowed 338 @.700
2.25 intake valve and 1.90 exh
RPM Pro I beam rods
GM steel crank
Dart Intake
custom built 4150 1150 cfm

the Cam would need to be a solid roller in the 270-275 range @ 50 with the lift in the .700-750 range.

Just a quick list to get you started:thumbsup:
 
#18 ·
I think that it sounds like a cool project also, and something worth shooting for. Just not with a 6,500 RPM limit. Just as Ray stated earlier, 6,500 RPM isn't going to get-R-done with a 396 CID. Another thing is, I gotta question the expectation of low 10's on 600 HP in a 3,400 lb car? I dunno about that, but perhaps some of the more experienced drag racers can weigh-in on that. You're definitely gonna need a hairy solid roller cam, and a healthy level of static compression ratio to make FULL use of such a cam. Not to mention either some good aftermarket heads or a great porting job on some stock heads (I dunno, the latter might be a longshot though).

I'm not claiming to be a cam expert here, but below might be the types of cams you would need. I don't mean that this company has the only good offerings, but just some examples here.....but by all means, consult an engine builder first! I'm merely throwing these out here for examples, or to promote further discussion as to what you'll need to obtain your power goal of 600 HP. So please don't misunderstand my post. Just talkin motor stuff here. I'm a typical motorhead, I just can't help it.:D

http://www.lunatipower.com/Product.aspx?id=2073&gid=253



or....



http://www.lunatipower.com/Product.aspx?id=2058&gid=249



or.....



http://www.lunatipower.com/Product.aspx?id=2055&gid=249
 
#22 ·
There many others that can give you advise on how to accomplish your desired results. From a very basic point of view....I see 383 small block crate engines advertised that will produce 500+ horse power. It would seem to me that you could make at least that with 402+ cubic inches and heads that breath far more than small block heads.
Am I missing something?
jim
 
#23 ·
Jim,
You were missing the part where he said 6500 rpm and 600 horse in the same sentence....
As most every one chimed in, 7500 or more, big cam, big heads.....to make that kinda power from a 396. Forget all about any street driving
 
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#24 ·
yeah...i did miss the 6500 rpm limit.

A 396/402/427 would be a costly build and have to rev to the moon for that kind of power.

is the 433 stroker just so odd (bore x stroke) that it's hard to make allot of horsepower with them? Seems like it just never is an option when folks want to use the 396/402 block. Other GM engines have odd bore to stroke configuation however it is costly and rare to hear about them making over 550 horsepower.
 
#31 ·
Hey Guys, I have a morning off after a few hectic work days and I was amazed at all the posts, many thanks. I have learned alot and have much to consider. I was kind of surprised that we can go over 6500 rpm with a 2 bolt and the general feeling is 600 HP is possible. I know it would be much more practicle to go larger on the cubes but the idea of using the small big block was something kicking around in my head. The article on "mean little rodent" was just a great read. I have a lot of work to do on the car before I even get to the motor but as I explained I'm starting to focus in on where I'm going with this project. Whatever way I decide to go with the motor I want to thank you all for your help. Gerard396
 
#32 ·
IMO you would have to have a well set-up 3500lb car to go 10.0s with 600hp. I am thinking more 10.30-10.50s. As far as 600hp I think goes it should be in reach. My friend built a 427+.030 for the street(10:0 to 1), edde ovals (no porting), XE solid roller (248/254@.50) and a 3500ish converter at 3550lbs it has run 10.60s. He shifts about 6800 and goes thru the lights arround 6500rpm. If he updated it to be more race, with head work, compression, and a race converter he could pickup quite a bit.
 
#33 ·
Hey Mike, thanks for the info. This would be a race only car and I figure on loosing some weight along the way and setting it up. I'm encouraged by your friends time and I would be happy with 10:30-10:50. Thats about what I am shooting for, and hopefully with time and effort I will get it. Thanks, Gerard396
 
#34 ·
Mine went 10.30's with the 427 at 3400 lbs. I think with better heads I could have probably gone 10.10-10.20's with what I had. I built mine in 1994 with rect port Merlin steel heads. A good 305 port aluminum head now, probably would have woke it up a bunch.
 
#35 ·
Hey Ray that's a mighty nice chevelle! I'm thinking those aluminum heads and a solid roller cam-todays technology. I see alot of sbc 383's and alot of BBC monster cubic inchers and I can appreciate both but why not use the same ideas in a 396/402/427 platform?? call me retro-ish from that point of view. I've looked at the stoker kits but its my impression a shorter stroke means it revs into power band quicker, but the stoker is an interesting concept also. I just need to do some more research.
 
#37 · (Edited)
My friend has a 383 in his Nova. It was originally built in 1997 I think. I doesn't have many runs on it, and it's all pretty much off the shelf stuff. After the last freshen up, the cam was changed and I think it made 615hp. It's gone 9.70's in a 2600 lbs car. It was just that for the same amount of money, he could have built something bigger and make the power easier. But it's what he wanted to do.
 
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