Aight guys..this is NOT goin in a thirdgen..BUT its goin in a bird ..
im building a 78 TA WS6 car..and im taking it from the frame up.
I have a `68 396 engine that i want to drop in it..and im engine stupid..so heres the deal....i ran all the cast numbers and found out its a 325HP engine and has 325HP heads...its a HI-PERF engine so im assuming that it has a forged crank..but im just guessing...anyway..im hoping that i can get 400-450HP out of it and keep the heads...i have a edelbrock 750cfm carb (new) ill use on it..and a performer rpm intake w/matching cam and lifters..from there im lost..i need to know if i can get that kinda juice out of it..and if you think its going to be a ***** to get that beast in my engine compartment any help will be GREATLY appreciated..thanx

 

easy swap

use 68 72 chevelle big block headers
use 70 and later chevelle BB long water pump and pulleys, and accessory brackets. and belts.
Cut /remove the pontiac/olds frame tabs (motor mount)
Use 70 72 chevelle frame tabs and motor mounts
Small block or big block doesn't matter as long as they match.
put the frame tabs on the motormounts on the motor
and put the motor and trans in the car. with the headers
line up the trans mount on the cross member and install all bolts
and install the drive shaft (shorty th 350) make sure the motor is square in the car and level on the frame.
It will be slightly offset to the passenger side but square
in the car. Get every thing lined up and then tack weld
the chevy frame tabs to the crossmember.
remove the motor mount thru bolts, trans mount center bolt
drive shaft, undo the headers. remove the motor and finish welding the frame tabs to the frame. use a chevelle/ camaro rad
and hoses and modify the shroud to clear the fan.

454 big blockchev 70 formula

 

You'll have no problems dropping a BBC into a second gen. There's more room than in a third gen.

To get 400-450 HP you'll need a bigger carb than a 750. An 850 should be used. The performer cam and intake won't get you that much HP out of a 396 either unlees you can spin it to 7000 rpm.

The old rating of 325 HP was at the crank with no accessories on the engine. It was a very inflated rating system back then.

The HI-PERF just means it's a car big block. Tall deck blocks that were in medium size trucks have TRUCK cast in them. The HI-PERF just means the big block is considered hi performance compared to a SBC.

What are the head castings?

 

heres what I found out about the heads:

casting # 3917215
valve int/exh 2.06/1.72
Chamber (cc) 100.967

Heres what i have on the block:
(does have HI-PERF and TRUCK stamped behind the flywheel)

Casting # 3916323
year 1968
engine 396
HP 325
2 Bolt main

and thanx to both of you guys for your help..im needing all the info I can get b4 i start this engine. thanx again.

 

just use the headers and frame mounts for 2nd gen camaro, the early ones did have big blocks from the factory and they do make 2nd gen big block headers, no need to use A-body parts

 

This is an ok engine. Not the best but you can easily obtain the power you want.

When you change the cam, MAKE SURE you change the springs, retainers and keepers (locks). A good time to change the push rods, also.

The big-blocks got a bad reputation when they first came out because everyone was used to the high-revving 283 and 327s. A lot of decent engines were destroyed trying to get them to turn 7,000 rpm with those very heavy valves and weak springs. I've seen many dropped valves from this.

A good set of roller-rockers will also be beneficial. You CANNOT use the stock 325-horse rockers with a high-lift cam (over .500 lift).

Keep the rpms under 6200-6500 and it should be ok (with the above mentioned parts).

The crank will be cast but if it is not messed up it will be ok.

My opinion on the carb would be ditch the Edelbrock and get a Holley in the 780 or 800 cfm range.

If you have the engine totally apart, check the ring land gap. I've seen many stock pistons become unusable with a too wide space between the ring and piston. Can cause flutter. Not good for rings.

While it is down, pocket port the heads. Cheap 20-30 horses.

Put in a good distributor, good fuel pump, good sub-frame connectors, decent rear gears (4.10 or so), fire it up and go out and have a great time eating LS1s.
jms

 

I don't even remember what the casting is of my block. I think it was from a 74 pickup truck. The BBC blocks didn't change that much so casting don't usually mean much. Just as long as you know that it's a 396, 402, 454 etc block.

My block is also a 2 bolt main but I used studs to make sure the bottom end can withstand the extra abuse. You'll need to get it line honed if you go to studs. My crank is also just a cast crank. Forged cranks are nice but not neccessary unless you dump a lot of NOS into the engine.

Personally I wouldn't go with those heads. They're small valves and closed chanber. You would be much better off with some open chamber heads like 049 or 781 castings. The open chamber heads unshroud the valves for better air flow. Have some 2.19/1.88 valves installed and do some port and polishing and they'll work much better than those 215 heads. If you need more compression then get the proper pistons to increase the compression.

You definitly won't build the type of HP you're expecting by using those heads.

As jms mentioned. Keep the rpms below 6500. Even with having the engine balanced, BBC parts are big and heavy. That's a lot of weight spinning around inside the engine. ARP everything. If you need to spin the engine faster then you need to start buying racing parts. Race pistons are considerably lighter as are aftermarket con rods (any brand or style will do). The lighter everything is, the easier and faster it can spin. Of course it all needs to be rebalanced.

 

Another site with lots of good big block info is www.chevelles.com
They have excellent forums and it seems most of them are into big blocks.

 

Stephen is right about the heads. They are the old closed-chamber kind, very prone to pinging and detonation. THey are a terrible choice for a street-driven big block.

Another better casting is the 292s from the early 70s 402, which are relatively plentiful. Stay away from 454 heads.

The warnings about the valve train are true. The rockers and valve springs are total garbage. You MUST get better valve springs to run a cam with very much more than .500" of lift.

It's even easier to get that motor into that chassis than f-bird 88 says. Camaros came with BBs in the early 70s, so there are plenty of headers available for that chassis, and they actually fit the car, unlike SB headers; small block and big block motor mounts are the same, so all you need is the ones for a V8 Camaro; short-shaft T-350 was the usual auto trans in those cars with the Chevy 350, so the driveshaft IIRC is the same as with the BOP 350; weight is about the same as the Pontiac motor so the front springs should be OK; you'll have to relocate the battery to the other side, no big deal if you find a junk Camaro; etc.

450 HP is a real stretch with the oval port heads. 400 is about a reasonable practical limit. You can get 500 ft-lbs of torque is built right. I'd recommend about a Comp XE274 cam.

 

The 325 horse 396 didn't come with a forged crank.
Still, if you feel you gotta have one,the short stroke big block forged cranks are all over the place used.Call some local machine shops.Usually everybody wants a 454, so the 396/427 cranks are cheap.I believe all Mark IV big blocks are marked "Hi Perf".
The closed chamber heads won't flow as good as the open chamber (1970+) design, but you'll need open chamber pistons to bring the CR back up.
Go easy on the Compression if it's gonna run on pump gas, big blocks are usually more detonation prone than small blocks.
As second gen camaros came with big blocks, the mounts are available from the reproduction co's.
Oval port heads work fine if pocket ported and bigger valves are installed.
My 396 (actually 1970 402) was a 350 horse.It now makes 510 horses at the flywheel with an Ultradyne Solid Lifter Cam (.601" lift exhaust), roller rockers,slightly ported oval port heads with 2.19/1.88 valves,a Performer RPM,800cfm Double-Pumper and 2-1/8" Headers.
(in my 70 Nova SS)
-Rich-

 

just wanted to thank all you guys for the info..ill have the engine done after i get all the stuff for it...cause im not gonna make this my learning engine ...i may have to use the stock heads tho and drop the HP down to 400...which is cool..im not wanting a super beast anyway, more of a kick *** street car...im completely rebuilding the heads anyway so the springs etc. will be new and ill get them ported like you guys said...thanx again for your help.