400 engine and 400 tranny - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sasktj · 12-12-2010, 12:49 AM

Im just going on what a friend told me back then and the fact that it hauled like crazy compared to what everyone else was running

3r!c84 · 12-12-2010, 12:50 AM

Compression yes. But flow I doubt it. Guys try (some do) put them on 350s and it's a dog. Worse then the stock heads. Go with a bigger valve head. Not a stock 305head
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sasktj · 12-12-2010, 12:57 AM

I agree. Im just saying what I did. Im not saying he should use 305 heads I was saying that he shouldn't destroke a 400. I was piecing together a 400 and the 305 heads were the best I had at the time condition wise

*nbpro* · 12-12-2010, 01:00 AM

The real problem with 305 heads on the big bore 400 is the fact that the tiny 305 combustion chambers are designed for the tiny 305 cylinders. When you bolt the 305 heads on the much larger 400 bore, you wind up with a combustion mismatch

once and for all i would like to clear this up. I said I was THINKING about destroking the engine. Something that I had read. With further reading, not just here, other places. It's not for me

*nbpro* · 12-12-2010, 10:39 PM

Quote:

Originally Posted by BigBlocksRule

I can't understand why anyone would want to lose displacement on an engine by destroking it. If that theory held water, there are a lot of folks out there making a mistake by building a 383 with a 400 crank.
Stick with stock stroke, toss the factory 400 rods - they're the weakest of the bunch - and get a set of stockers resized. Vortec heads and a decent cam will give you all the power you want.
The destroker will only rev a few hundred rpm's over the 400, maybe a fraction quicker - and he'll be behind you, trying to catch up. Extra cubes = extra torque
BTW, the factory 400 crank is nodular iron, same thing Eagle and Scat uses in their "cast steel" cranks.

BigBlocksRule (are any one )what is a good casting number or numbers for the Vortec heads and a cam to match ?

BigBlocksRule · 12-12-2010, 11:06 PM

The very earliest 906 castings had seats that hung way over into the port. Any after those would be fine, I'm not partial to either one. Leave the studs as-is, I haven't seen one pull out. Keep in mind that a 400 will want a bigger cam than a 350 would. Something in the 224 - 230 range would make a nice driver, it'll start getting pretty lumpy around 236 intake duration, worth either way from there.

12-12-2010, 12:49 AM	#26
sasktj Registered User Join Date: Nov 2010 Location: Saskatoon Saskatchewan Posts: 5	Re: 400 engine and 400 tranny Im just going on what a friend told me back then and the fact that it hauled like crazy compared to what everyone else was running

12-12-2010, 12:50 AM	#27
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 400 engine and 400 tranny Compression yes. But flow I doubt it. Guys try (some do) put them on 350s and it's a dog. Worse then the stock heads. Go with a bigger valve head. Not a stock 305head Posted via Mobile Device __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

12-12-2010, 12:57 AM	#28
sasktj Registered User Join Date: Nov 2010 Location: Saskatoon Saskatchewan Posts: 5	Re: 400 engine and 400 tranny I agree. Im just saying what I did. Im not saying he should use 305 heads I was saying that he shouldn't destroke a 400. I was piecing together a 400 and the 305 heads were the best I had at the time condition wise

12-12-2010, 01:00 AM	#29
nbpro Account Suspended Join Date: Dec 2008 Location: Huntsville,AL Posts: 2,119	Re: 400 engine and 400 tranny The real problem with 305 heads on the big bore 400 is the fact that the tiny 305 combustion chambers are designed for the tiny 305 cylinders. When you bolt the 305 heads on the much larger 400 bore, you wind up with a combustion mismatch once and for all i would like to clear this up. I said I was THINKING about destroking the engine. Something that I had read. With further reading, not just here, other places. It's not for me Last edited by nbpro; 12-12-2010 at 02:34 AM.

12-12-2010, 11:06 PM	#31
BigBlocksRule Registered User Join Date: Jun 2008 Location: Lubbock, TX Posts: 2,047	Re: 400 engine and 400 tranny The very earliest 906 castings had seats that hung way over into the port. Any after those would be fine, I'm not partial to either one. Leave the studs as-is, I haven't seen one pull out. Keep in mind that a 400 will want a bigger cam than a 350 would. Something in the 224 - 230 range would make a nice driver, it'll start getting pretty lumpy around 236 intake duration, worth either way from there.



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