Thread: 350 chev vs. 400 chev

Tweet

I recently came into posession of a '77 chev 400 motor, small block,looks to be in good shape, can anyone tell me briefly the pros and cons of using this motor instead of a 350?

needs external balanced flywheel/harmonic dampner-------if its complete engine everything compatibal---mounts, exhaust, accessories

I have the truck, so it is all there. Flywheel is cracked but that can be replaced easy enough. (motor/trans already removed) I was asking in terms of reliability and what kind of cost comparisons in improving on power. I know most parts are interchangeable but I would think the 350 would have less expensive parts inside as the 350 was produced in much larger quantities. On the other hand I have heard(and read) both good and bad things about the 400. Also, in checking prices it seems the 400's cost quite a bit more if one was to buy a complete motor.

Price of what parts? Doubt there's enough difference in 350 and 400 internals to even make it a consideration. 400 has a longer stroker and makes more torque, probably better for a stock type rebuild for a truck. I'd have to suggest you consider which would provide you the best engine for your application rather then just counting the pennies.......

Some folks don't put much stock in the 400 because of the siamesed cylinder walls, claim they cause heating problems, and the external balance bothers some; the heads are also different, have some extra steam venting holes in them that the 350 heads don't, and it has been said that the 400 heads are prone to cracking. That said, I never had any problems with the 400s I had in my trucks, and I worked them pretty hard; in my experience they are good engines, and given the choice, I would take a 400 over a 350; appropriately massaged, they will make excellent power and be dependable doing it.

400's are horrible,and as a real pal,I'll offer to sacrifice myself by letting you give it to me. I'll put up with drilling steam holes to swap in 350 heads and the horror of using reduced base circle cams to clear the crank. Hank

Reduced base circle cams? By that you mean there are special cams for the 400? I have a retro-fit roller cam for a 350, but if I cant use it then the price of improvement just went up. I have read of cracking problems with the stock heads but I also have some good 350 heads, should I put them on instead? How about you stop beating around the bush?

Hey Pat, can you give me the real story on the 400?

If I didnt have to count pennies I'd be drivin a Ferrari

Check with your cam manufacturer to see if the one you already have will work in a 400. I used early 327 heads and just drilled the steam holes myself. You may not want to increase the compression that much. Quite a few late seventies chevy heads were prone to cracking not just on 400's. Hank

Originally Posted by halftanked

Check with your cam manufacturer to see if the one you already have will work in a 400. I used early 327 heads and just drilled the steam holes myself. You may not want to increase the compression that much. Quite a few late seventies chevy heads were prone to cracking not just on 400's. Hank

and he didn`t beat around the bush ,,,

I always thought it was inferior to 350. I always heard just like 400 Mopar is inferior to 383,400 Ford inferior to 390,360 Mopar inferior to 340. I' can't verify 350- 400 but the others are all true lol. That I can verify!!

Comparing a 400 Ford to a 390 Ford is light comparing an apple to an orange! They are 2 different engine designs / families.. The 400, known as a Modified, and the 390 known as the FE. Completely different designs and intended uses.

The 340 / 360 comparison.. I've never heard anyone ever say a 360 was inferior to a 340!

Perhaps it's a regional thing?

I meant when I was looking to buy a late 60's early 70's Ford everybody said make sure you get a late 60's cuz 390 is a lot more durable and has more horsepower. Same when I was looking for a Duster everybody said get a 340 their a lot hotter. That's what I meant not internals and such. We on the same page now?
Oh apples and oranges are both fruit ,round and grow on trees close enough. Its not like comparing an orange to a basketball lol.

If you were raised in a Mopar family like I was you would hear the 383-400 340-360 comparisons often and 400 and 360 would always coome up short. More cubic inches less horsepower does not weigh heavily in their favor...

That is not true that the 390-400 came in different cars with different intentions. IT replaced 390 in all cars LTD,Galaxie,Montego,Marquis etc... I won't go on but it was all of them rest assured.