'78 6.6L 400 + '72 vette 350 heads?
08-08-2005, 01:17 PM
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'78 6.6L 400 + '72 vette 350 heads? I don't know much about second gens/400 ci's, but what I do know is usually you want to match heads (i.e.:350 w/ 350 and 305 w/ 305). Is the 400 ci w/ 72 vette 350 heads any good or will I be losing power? Heads are ported and polished. Also, where can i find more information on this?
08-09-2005, 04:36 PM
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Need to get the head casting number and I would consider posting this in the small block forum. I can kinda guess which heads they are and with a little bench work , should be ok. The 400 is a good motor but it does tend to get hotter than a 350 due to the fact it's been punched out so big. Thus it is more prone to overheat.
08-09-2005, 05:37 PM
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#1-The heads would need to be drilled for steam holes for use with the 400 motor
#2-Being a 78 version 400 it'd be pretty low compression I'm guessing unless you plan on changing pistons
#3-If money allows I'd use aftermarket heads. More power to be had (and in using aluminum heads case, cooler temps)
Just my thoughts...
Derek
#2-Being a 78 version 400 it'd be pretty low compression I'm guessing unless you plan on changing pistons
#3-If money allows I'd use aftermarket heads. More power to be had (and in using aluminum heads case, cooler temps)
Just my thoughts...
Derek
08-09-2005, 06:12 PM
#4
Back in the day (read, 10-15 whole years ago), I knew a lot of people who would tell me their 350 had 305 heads like it was a good thing. Just a bit of info there.
I'm not pretending to be an expert, but I do know some build philosophy has changed in the last 10 years or so. Look at what our small blocks are displacing now.
Internet message board disclaimer: I know what heads are and I know what they do, but that doesn't change the fact that people put smaller heads on V8's when I wore a spike mullet and Rebock Pumps and before. Jump in your time machine and argue with them, not me.
If your 400 has 350 heads on it, it's because someone thought that they were a good thing.
I'm not pretending to be an expert, but I do know some build philosophy has changed in the last 10 years or so. Look at what our small blocks are displacing now.
Internet message board disclaimer: I know what heads are and I know what they do, but that doesn't change the fact that people put smaller heads on V8's when I wore a spike mullet and Rebock Pumps and before. Jump in your time machine and argue with them, not me.
If your 400 has 350 heads on it, it's because someone thought that they were a good thing.
08-09-2005, 06:33 PM
#5
Oh, and it's a first generation Chevy engine, regardless of what gen body style it's in. First generation encompasses anything from the first small block to a 454 truck engine to a TPI 305 and everything in-between.
Chevy didn't come up with the "generation" gimmick until 1992. A second gen is an LT1 or LT4, third gen is an LS1 or LS6, and a fourth gen is an LS2 or LS7.
Most people who deal primarily in Gen I engines don't know or care about the whole "generation" thing; that stuff for us LT1/LS1 guys.
My suggestion would be to talk to your local engine builder about your question. If it were my engine, and I wanted to put some money into it, I'd have my engine builder bore it to 406 and I'd buy the aftermarket heads, intake and carburetor of his suggestion. Tell him you want it to put out 400 horse power and that you're not scared of a big cam.
Don't spend more than $4000 on the whole thing, though. I spent about $3500 on my 383 and it was a beast, but it had stock ported and polished (350) heads. Don't remember the castings; it was my first car and I was 16. I just wanted to go fast.
Ahhh... the memories.
Chevy didn't come up with the "generation" gimmick until 1992. A second gen is an LT1 or LT4, third gen is an LS1 or LS6, and a fourth gen is an LS2 or LS7.
Most people who deal primarily in Gen I engines don't know or care about the whole "generation" thing; that stuff for us LT1/LS1 guys.
My suggestion would be to talk to your local engine builder about your question. If it were my engine, and I wanted to put some money into it, I'd have my engine builder bore it to 406 and I'd buy the aftermarket heads, intake and carburetor of his suggestion. Tell him you want it to put out 400 horse power and that you're not scared of a big cam.
Don't spend more than $4000 on the whole thing, though. I spent about $3500 on my 383 and it was a beast, but it had stock ported and polished (350) heads. Don't remember the castings; it was my first car and I was 16. I just wanted to go fast.
Ahhh... the memories.
08-17-2005, 11:23 PM
#6
The key with a big inch small block is head and cam selection. With 400 CID on hand you can go with fairly big heads. I would junk the stock ones as they are probably smog heads and not worth it. Everything depends on your budget. If you have the money go find some aftermarket aluminum heads and cam matched to the heads and you will be happy. If not, then a pair of Vortecs will do you just fine. basically they are cast iron LT1 one heads with normal cooling as opposed to reverse cooling. They are a really good budget cast iron head. You can get them new from a GM dealer for about $525 or you can go scrounge the junk yard.
