Never done a big block before so this is kind of new territory to me... The short block is the 350hp 396. (cast internals?) Going to keep that as it was recently freshened up. This is going in a ~3300 lb car, T56 with 411's. Trying to make it as "rowdy" as I can while maintaining a useable 6th gear on the highway. Thinking about using the AFR 290cc heads and shooting for a bit under 11:1 compression. Still undecided on solid roller or hydraulic roller... I love the SR in the 406 we just did but it is a pretty tame solid with low spring pressures so adjusting the valves is really just a matter of checking them. They dont seem to move at all.
What say the all-knowing CF motor heads?

 

I used to run a 396 in a 67 Chevelle, with a Crower .517/.530 solid. I don't think they even make that grind anymore. Best run was 12.45 @ 107 mph.

Although I did enjoy my 396, I can't imagine that one of these motors is going to impress someone that Im guessing has been running a 427 sbc.

Don't get me wrong, a 396 can be a real nice piece, but for the extra weight when compared to the sbc type cubes, its just so hard to recommend going in this direction.

Im sure a cam could be swapped into this combo that could be a real screamer. Check out www.chevelles.com and poke around, or even post this question there for a wider array of answers.

 

That's a lot of $$$ of head to spend on a cast internal 396. There's a lot of GM iron oval port 496's making 650-750 HP out there. Certainly the 290's are too much for a 396 like you're describing. The 265's would be a better choice.

But I'd put together a 496 with good GM iron ovals before I'd spend that much on a set of heads for a 396.

JIM

 

11 to 1 internally balanced BBC, 6 speed manual and 4.11 is really made for RPM and a nice solid roller, that is coming from a hydraulic roller fan that has a 4.11, T56 and 10.4 to 1 hydraulic roller 383. You have a solid roller, like it and know what is involved. The AFR 265 oval ports are a great choice. Really good exhaust port, I/E ratio so a single pattern cam if you have 2" primary headers, good free flowing exhaust. If it is a stock crank it is probably nodular iron not regular cast and 3.76 stroke which is real forgiving HP and RPM. BBC is Heavy duty compared to SBC. Think of the 396 as as a big block version of a 302. I would want a tight lash cam to minimize issues. Look at this one. http://www.summitracing.com/parts/cc...make/chevrolet
8.4 DCR so get quench right and you will be good on premium. It will pull fine cruising on the highway with the heads and cam and pull hard to 7000 RPM. Get the AFR # 8000 spring option on the heads. Better if you are a little under 11 to 1 if possible. The operating RPM is probably for a 454 so move it up a little when you look at those numbers.

Edit: Price isn't bad!! http://www.summitracing.com/parts/afr-3620/overview/

 

You're going to have to whack the open chamber heads a LOT to get 11.0 compression on a 396 with even original 350HP pistons. If it's been rebuilt there's a good chance they are replacement *universal* pistons that have a weird dome with 2 valve notches and a ton of deck clearance. And a cast piston 396 is good for 6000+ rpm for a little while...but the pistons will give up eventually. The bottom end otherwise is fine.

I've run 396's deep into the 11's with cast pistons and iron oval ports using solid flat tappet cams. Frankly I trust the factory OEM pistons in an old motor more than most replacement cast pistons.

They WILL run hard....but a good piston would be a plus if you're planning aftermarket heads and a roller cam $$. Again...at this point you're only the cost of a 454 block away from building a 496/505 and making an extra 100-200 HP.


JIM

 

427Hotrod is right, You can get an extra 100-200 HP and gobs more torque if you increase displacement 100-150 CI. That said it will require a complete new build, forged parts and a $2000 set of heads and a stock differential won't cut it. If you have a solid short block the advantage to a short stroke big block build is it will wind tight and quick, won't have the huge low-middle torque numbers, piston speed is lower, much easier on drivetrain and engine internals and will match your T56, 4.11 well. Cast pistons is the only weak point but the taller smaller bore piston and slower piston speed of your 3.76 stroke will cushion that. You will be more than capable of keeping it in the fat part of the powerband at all times with your gearing and highway cruise is no problem. There is always something faster but I think this is a 525-550 HP build that will hold up well, be really fun to drive, versatile, great total combination and won't break the bank. Your talking $3-4,000 total vs $10- 12,000 plus drivetrain upgrades for the build. If you have a good intake and exhaust now your closer to $3000 than $4,000. A lot of guys bussing these 396-402 to 7000 shift points with stock type bottom ends. A lot tougher with 496-540 CI. Piston speed kills engines.

 

Thanks for the responses
The motor isnt for my car, a friend asked to help set up his motor while we do a 6 speed swap on it (69 nova). Not trying to be the fastest on the street, just wants to be able to roast some tires at a moments notice
Ive always found that Ive "under headed" my motors (195's on a 406 and 180's on a 350 ) because I was scared Id have no port velocity and it wouldnt be 6speed friendly. I didnt want to do that here, but not knowing much about what BBs like I guess the 290 is a little too big for a 396. With that in mind and the 265 AFR's being discussed, are there any other heads you might recommend? alu preferred.
After Jims comment about the deck height with replacement pistons the whole 396 thing may be a wash if they are sunk in the hole too far. We will see once we start the tear-down! Any tips on valvetrain components for big blocks with an SR cam to try and keep things from moving around too much? I doubt this thing will see north of 6500RPM

 

With the tight lash and limiting RPM a billet cam and Isky red zone lifters are probably overkill. Good full roller rocker arms with poly locks are a good investment. I use these with bigger spring pressures. Good quality without breaking the bank. http://www.summitracing.com/parts/cc...make/chevrolet
You can run the lash a little tighter on this cam too, .016.

 

I agree with Jim, if you're gonna build a BBC and its not an original/restoration type build... then do a 454.... Way cheaper, way more power across the board..

My dad and I just built a .060 396 for his 65' vette, a resto/stock appearing build... It turned into a VERY costly build and really didn't make that great of power(441hp) considering what we spent and the killer bottom end parts we put in it...(stock heads, stock intake and stock exhaust manifolds were the HP killer for us)..

I will tell you that custom RaceTec pistons for a .060 396 with close chamber shaped domes are $700, they have to be custom made.... Other wise you are stuck with stock TRW/Sealed Power 11.0-1 dome pistons that are heavy as hell... or flat top pistons you can't get any compression with.

You can build a 500hp 454 for PEANUTS....and make much more torque and better power band....

For what you will spend on a set of AFR heads, you can just about build a 454 for..

If you DO decide to build a 396, make sure the valve spacing on whatever heads you run will clear the cylinder bores on a 396... The AFR 265 ovals would be a great head IF the valves will clear the cylinder walls... May have to notch the cyls. Then a good custom roller cam, single plane intake, 750 or 850 carb and good bottom end parts so you can spin it to make the power..

Honestly I think you'll spend more on a 396 to make the same 550hp you could make with a moderately built 454.

 

If you are wanting around 450HP then stock heads and a hyd roller will get you where you want to be. If you wanting 500HP plus then a set of AFR265 and a hyd roller will achieve this with no problem. I would run an Edddy RPM or Air gap under the hood with either head along with a good 850HP

 

You got all the stars chiming in.

Now make wit' da build...

Carter

 

A hydraulic roller will work fine for your needs but you seemed to be more inclined toward a solid roller. Pro's and cons to both.

 

This is a hyd roller. OEM headed 427. 229/241 .050" 109 Sep Runs the fast EFI.

 

I'm surprised the idle is so smooth with that cam.

 

I have to ASSUME you say that because of the lobe sep. This this why I say you can't judge a cam by it's LSA. That cam will produce 11" of vacuum.

 

I'm saying this based on this cam's 76 degrees of overlap (based on advertised duration) and 17 degrees overlap at .050.

http://www.claysmithcams.com/bbc-454...x-of-5700-rpm/

 

If the valve events are correct, letting air/fuel in at designed time and letting exhaust out at the right time the idle note will be crisp, not lazy, and vac will be present. That has been my findings.

 

The AFR 265 is actually one of the least expensive name brand aluminum heads you can buy and they flow more than most 290 and many bigger heads flow. You need to get to the tear down stage and get some piston and deck height information before you can make a decision or other can give accurate recommendations. Owner needs to decide on hydraulic roller or solid.

 

For the cost of the AFR290's you can damn near get AFR265s, roller cam, and lifters.

 

Just curious, does this Chevelle have the same cam as the Corvette above?