I'm getting close to putting a motor back in my 68 chevelle but i'm torn between two motors. I have two to choose from. A 396 or 355.
the 355
4-bolt main
stock crank
polished pink rods
performer rpm intake
750 double pumper
afr 210cc 2.08int 1.6exh
comp extrem cam 274 .487/.490
crane roller rockers

the 396
steel crank
cast pistons
torker 2 intake
750 double pumper
cam?
crane roller rockers
stock heads

The 355 is freshly rebuilt with no miles, and the 396 has about 3000 miles on it. The 396 needs a balancer, pulleys, and a new oil pan because my friend has a really exspensive one and he wants it back. THe 355 is about $2000 and the 396 is $1400 plus the extra stuff i still need. The 396 is a 68 block the same year as my car. I just don't know which one to put in. If i put the 396 in what do i have to change going from a 350 to a big block? I have a 4-speed tranny.

thanks
lucky3

Go with the big block, no doubt. Just put it in with your 350 engine mounts, no problem. The small block sounds nice, but with a big block on hand there is no question, at least for me! I like big blocks about as much as DZ likes 4 speeds...just a little biased http://www.chevelles.com/forum/smile.gif http://www.chevelles.com/forum/wink.gif

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

You'll need all the brackets, etc, for the BB, and I would recommend you run at least a 1" sway bar in the front. It seems to really help cornering with the extra weight. You may or may not need stiffer front springs.

There's just something about a rat in a Chevelle. Match made in heaven IMHO. If nothing else you'll enjoy the extra tork.

There is no replacement for displacement.This a decision you have you have to make for yourself as you will be the one driving, maintaining etc.Myself,well I say big block all the way.The 396 will fit in place of the 350 using the same mounts,flywheel and mounting hardware.The front springs should be replaced with heavier duty big block items.But to be factory correct you will need to use big block frame mounts and big block z-bar and linkage.

Since you have that kind of choice,--------- there is no choice. The 396. End of discussion.

The parts you need to complete the 396 are/should be relatively easy to scrounge up. Personally, myself, I would devote most of my parts search for a correct Chevelle pan. They're out there, you may have to look a little. Check with the TC ads or place a want ad on TC.
Actually, I should have ask first thing, do you know for a fact that the 396 is a good, non-oil burning, well built engine? If so, do it.
The thing about it is, if at a later date down the road, you want to go bigger BB, you're set.
You say you have a 4sp. Do you have a 14in (11in clutch) flywheel/big bell housing? If so, you're set. I don't know what you have in mind for headers, but the Dynomax ceramic from Summit are the same price, BB/SB, doesn't matter. The 355 is a little easier to work on, lighter, better gas mileage,------------------------- but IT AIN'T A BB! My 70 conv is a strong SB406. My son's 71 is a BB408. The difference is night and day! Period. We built what we had to work with, with the thought in mind that when a 454 block/crank came along (and some money for parts/machine work), we could use everything we have now on the 454. And I still think that was a good decission.

By the way, since you have to change pans, check to see if the 396 has a windage tray. If not, all you need is the 4 studs and tray from Chev. Change the bolts to studs one at a time and you will be OK.

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Tom Parsons

I dont know if the chevelle has its own pan. I have been moving big blocks around for awhile and havent had any problems with the normal rear sump pan, including 454s from pickups that I have put in chevelles, camaros, and novas. I even used the standard pan in my 55 tight as a bitch with the rear steering but it goes.

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

The big block is from a friend of my and we spent about 4hrs looking through, testing , driving and talking about the motor and whats done to it. It doesn't smoke and it runs good and strong, the only thing is the person who built it had little for bearing clearance so it runs about 90psi oil pressure until it warms up then it drops to about 60psi. I believe he said thats why it runs such high oil pressure. The oil pressure is the only thing that makes me think twice about the motor.

I would go for the 355 it sounds like a
better and faster motor. Small blocks can't be beat for the price, gas savings and reliability over a big block. Plus the weight savings will make your car handle better.

Atlast, I think this time the SB can be beat for price. The SB is $600 more than the BB although the BB does need some accesories to finish so it might be a wash. Good point about weight though. DZ makes a nice point about upgrading later. If you think you may go bigger then definately go BB as you will already have everything and the money can be spent on the motor and not parts to do the swap. Don't know about the oil pressure thing though. There are good and bad about both but just my opinion only is everyone has a small block and I am just not impressed anymore. Big blocks just belong in a musclecar, especially in a Chevelle. Before you small block lovers tell me I'm a idiot I have a SB 400 that I absolutely love. But starting out if I had a choice on which to buy its BB almost all the time. It depends what your future plans are for the car I guess.

Lucky, I sold a 396 a few months back. Ran mint, no oil smoke, but it friggin' pegged my oil pressure guage ( factory SS guages so I don;t know the actual psi). The L88 I replaced it with had 65psi on cold start and 30-40 warm at idle. It definitely did not peg the guage so I figure 90 psi.

Could it be a high pressure oil pump in there? They were the "trick" deal back a few years ago.

If it is, me, I;d replace it with a stock or a high volume pump, but would ditch the high pressure. No big deal. $30 and a drop of braze to secure the pickup.

Or better, use a 7 qt L88 pan with windage clearance and install the correspondind pump/pickup.

I'd go for the 396 for the same reasons the others have metioned plus the WOW factor. I swapped the LT1 that I had been running for years in my 72 Chevelle for a 402 as it was originally equipped with this past summer, and even though my small block had earned a lot of respect around my home town, the appearance of a big block under the hood of a Chevelle just screams "look at me, I'm a bad a$$!!!" even if it really isn't. They just look tough.

Also if you go to sell the car, big block cars, original or not, are what people with the big bucks go looking for. Big block is a much quicker sell.

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Steve

72 Chevelle SS402/4sp