76 sbc 400

[pbzzz]

I have an ALL ORIGINAL 72 c10 350ci/quadrajet that we occasionally tow our rv with . I have rebuilt/warmed over a 1976 sbc400 which is ready to be swapped in. ?Question is - can I use the water pump and pulleys from the current/original 350 on the 400 I am swapping in.? If so I believe I should have no problems with pulley(s) alignment, etc.

[Mike C]

Should be no problem. FYI you can buy pulley shims for minor misalignment issues.

Personally, for the work it takes versus what it costs, I would put a new water pump on.

[hugger6933]

You will be fine with your acc. drive the diff is inside the motor[ well except for the number or freeze plugs and balancer/flywheel]

[mike16]

I agree with Mike. those 400's were notorious for overheating and cracking the block. good insurance would be to put a new pump on it

[pbzzz]

thanks to all for responses... I was planning on putting a new one on. I just wanted to make sure there weren't any unknown (to me) problems with running the 350 style water pump and pulleys on the 400. thanks all again !

[68Gold/white]

Make sure you get the water pump for the specific 76 350 application. 76 is a one year, by itself part. Pumps before and after look like it, but something about it is slightly different.

[57taskforce]

Originally Posted by 68Gold/white

Make sure you get the water pump for the specific 76 350 application. 76 is a one year, by itself part. Pumps before and after look like it, but something about it is slightly different.

??? Never heard that one before... I’m betting he’s wanting to keep the short water pump and accessories original to the truck.

[68Gold/white]

I sold auto parts for 13 years, back in the days those water pumps were used. Next time you are at auto parts store, ask if a 75, 76 and 77 pump(s) are same...

I was asleep at the wheel, since he wanted to keep the 72 pump and pulleys/brackets on the 400, I also confirm that the 72 setup will bolt up to the 400, also!!!

[pbzzz]

57task - you read me right... wanting to use the original (72) type wa-pump and pulleys on the 400 going in it. My understanding is you are all saying I can do that without problemss. thanks all

[68Gold/white]

Originally Posted by pbzzz

57task - you read me right... wanting to use the original (72) type wa-pump and pulleys on the 400 going in it. My understanding is you are all saying I can do that without problemss. thanks all

Yes, you should be good!!!

If you were trying to swap in an older 183 or 327 that has NO holes in the end of the heads, you'd have to take a different route!!!

[KQQL IT]

Originally Posted by mike16

I agree with Mike. those 400's were notorious for overheating and cracking the block. good insurance would be to put a new pump on it

No. No they're not with a adequate radiator and a decent fan.
I've had 4 or 5 400 SBC and not one ran 'hot' my current one makes 500 ish hp and runs on the 160° t-stat

[68Gold/white]

Originally Posted by KQQL IT

No. No they're not with a adequate radiator and a decent fan.
I've had 4 or 5 400 SBC and not one ran 'hot' my current one makes 500 ish hp and runs on the 160° t-stat

I agree!!!

Any engine can run hot. Lack of cooling system maintenance can cause problems with any engine, a 400 included.

SBC 400's are awesome engines!!! I've seen several run for years, zero cooling issues. I have one slated for my 67 C-10 LWB, can't wait to get that thing going!!!

I HAVE heard of folks with SBC 400 cooling issues, the end problems had nothing to do with the fact that the engine was a 400...........

[mike16]

what ever . they had cooling problems. a statistical sample of two people is hardly conclusive.

bottom line. Keep it cool ....or else

[Jrainman]

You can use your same water pump and pullys from that 350 with no issues

I would say they are not notorious for over heating falure ,but they can be prone to over heating because the 400 block has siamse cylinder bore, witch required the heads to be drilled for steam relief , so they are one off heads on the 400 and reqiure correct parts and gaskets , they were never made for performance but from 1971- 1976 they used them in a lot of cars and trucks , I just picked up a 71 impala with a stock 265 HP 400 in it, the car was shot but the low miledge 400 turned rite over and it was sitting for a lot of years ,not that I am a fan of them but if put together rite they will run good.

[sawmilldmax]

I'm sure you're planning on using the flex plate or flywheel off the 400 since it is externally balanced. you'll love the extra torque of that 400. I think the later ones had only two freeze plugs on each side and maybe a flat spot where the third one goes.

[mike16]

put together right? Everything I read says they can crack a block if they over heat. drilling steam holes to improve factory cooling. They still crack and thats why there are so few of them. They are the ideal block to have when one combines them with a 350 crank to produce a 377. but they crack. they crack they crack they crack. do all the cooling mods you can to keep them cooled. But otherwise plan eventualy on them cracking and you may only maybe get a .030 over bore out of them which will increase the odds of overheating and then... they crack. thats why the 383 became popular. too many 400 cranks and not enough 400 blocks. And its not just me saying it. everybody from smokey yunick, to David vizard states they crack. Its a novelty, fun to show off but you are bucks ahead with a 350. I thought by now, almost 50 years later that was common knowledge......

[KQQL IT]

Originally Posted by mike16

what ever . they had cooling problems. a statistical sample of two people is hardly conclusive.

bottom line. Keep it cool ....or else

Right. And how many sbc 400 have you had ?

[geezer#99]

I built 377’s from free 400 blocks. Local wrecker dropped them off, I pulled them apart and kept the block, he came and picked up the rest. A win-win for both of us. Free block for me, easier sales on parts for him. Everybody was building 383’s and he had the cranks.
In the three seasons of racing I used 60 blocks. All well seasoned high mile blocks. Only one of the 60 wasn’t useable because it was cracked.
They don’t all crack, they just have that reputation.
I cracked the other 59 myself.
They didn’t like the 14 to 1 compression and 7500 rpm runs.
Had fun though.
Got smart and went big block.

[57taskforce]

Originally Posted by mike16

put together right? Everything I read says they can crack a block if they over heat. drilling steam holes to improve factory cooling. They still crack and thats why there are so few of them. They are the ideal block to have when one combines them with a 350 crank to produce a 377. but they crack. they crack they crack they crack. do all the cooling mods you can to keep them cooled. But otherwise plan eventualy on them cracking and you may only maybe get a .030 over bore out of them which will increase the odds of overheating and then... they crack. thats why the 383 became popular. too many 400 cranks and not enough 400 blocks. And its not just me saying it. everybody from smokey yunick, to David vizard states they crack. Its a novelty, fun to show off but you are bucks ahead with a 350. I thought by now, almost 50 years later that was common knowledge......

Did the 400sbc take your lunch money in elementary school??

[Steeveedee]

When the '71s came out, we had a massive amount of the 400 SBC come back in for work due to overheating. Ever seen a blue torque converter? They were usually big station wagons with AC...and a two row radiator. GM cheaped out on it, and it cost 'em for the mistake. That got fixed, and GM didn't try that stunt again.

[davischevy]

I bought a 76 K10 new with a sb 400. I blew a head gasket at about 50,000 miles, but it ran great until I sold it in 1980.


I'm almost afraid to go out to the shop knowing the 377 stroker I've been running the last 24 years is going to crack and run hot. I guess it didn't get the memo.

[Coley]

Undoubtedly the guys who were cracking these all the times were probably guys mounting double bump heads or similar on them without drilling/adding steam holes.
'hey...its a small block chevy right, put some high compression heads on it and let's go...lol'
Weekend warrior, beginners mistake I guess....and very likely responsible for probably 1/2 (or more) of the stories regarding the overheat issue.

The issue certainly wouldn't concern me if I was working to mount a 400 sbc in my truck.....which I just might do over the next year or two.
Of course...I'll make sure any head that goes on that engine will have the steam holes drilled in it....lol.

my two bits.
Coley

[davischevy]

In full disclosure, my 377 was built by a very competent engine builder and has Dart S/R heads.

[Boog]

Under "normal" use a 400 should have had a long service life. Extreme use would show up any weak spots.
A young fella came to me on a Sunday afternoon looking for 1 good head. He had a 400 with a bad head and needed it back together. It's all he had. I think I gave him a 305 head that was still tight. He put it on, mismatch and all, and I never heard if it worked out for him or not.
How much weight difference is there between a 402 bb and a 400 sb? Wouldn't it be more worthwhile to just go with a bb for the power and torque over a sb?

[davischevy]

100 lbs difference, and you already know I'm a big block man.