406 4-bolt or 408 2-bolt?
10-20-2003, 12:11 AM
#1
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Car: '01 sonoma & '91 camaro
406 4-bolt or 408 2-bolt?
I already ressurrected an old post, but in case you didnt see it I figured I would ask here.
I have a pre-built 406 2-bolt (817 block) that has some minor scores in the bores and one cylinder with some moisture that got in it (light surface rust). It has a nice set of pistons and 882 heads (untouched).
The other is a 400 virgin bore 4-bolt (511 block) that looks very clean. Everything on/in the motor is original.
Would you:
1. Re-hone the 406 and keep the existing parts
2. Bore 406 to 408 and have to buy new pistons
3. Bore 400 to 406 and reuse .030 over pistons an have a 406 block left over you dont know what to do with
4. Other (reply to post)
I have a pre-built 406 2-bolt (817 block) that has some minor scores in the bores and one cylinder with some moisture that got in it (light surface rust). It has a nice set of pistons and 882 heads (untouched).
The other is a 400 virgin bore 4-bolt (511 block) that looks very clean. Everything on/in the motor is original.
Would you:
1. Re-hone the 406 and keep the existing parts
2. Bore 406 to 408 and have to buy new pistons
3. Bore 400 to 406 and reuse .030 over pistons an have a 406 block left over you dont know what to do with
4. Other (reply to post)
10-20-2003, 01:06 AM
#2
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Any of those paths will get you there.
But using the 882 heads will be your downfall.
Absolutely no performance there.
Once you get beyond the 882's the rest is almost goof proof.
Pick another cylinder head. Any!!! other cylinder head!!!!
But using the 882 heads will be your downfall.
Absolutely no performance there.
Once you get beyond the 882's the rest is almost goof proof.
Pick another cylinder head. Any!!! other cylinder head!!!!
10-20-2003, 02:51 AM
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I have been kicking around the idea of Vortecs but wasn't sure if they would be to small. But the 882's are that bad, huh?
The pistons in the motor are TRW forged aluminum flat tops with a 2 valve relief. I have been trying to find some specs on them but havent had much luck yet. I would like to go with either 5.7 or 6" rods but I'm not sure that there aren't 5.7 rods in it now.
On the other post I had mentioned I would consider converting to a roller motor. The main reason I said that is for the TBI. I have searched on here and all the posts I have read said that the FI works better on a roller setup.
I cant say I am on a strict budget but, I would like to be reasonable also. I am thinking 400-430 hp and 430-460 lb-ft of torque should not be that difficult to make. My main issue is which block to use and how to upgrade my TBI system to handle this motor without spending $1000+ just on the injection system.
The pistons in the motor are TRW forged aluminum flat tops with a 2 valve relief. I have been trying to find some specs on them but havent had much luck yet. I would like to go with either 5.7 or 6" rods but I'm not sure that there aren't 5.7 rods in it now.
On the other post I had mentioned I would consider converting to a roller motor. The main reason I said that is for the TBI. I have searched on here and all the posts I have read said that the FI works better on a roller setup.
I cant say I am on a strict budget but, I would like to be reasonable also. I am thinking 400-430 hp and 430-460 lb-ft of torque should not be that difficult to make. My main issue is which block to use and how to upgrade my TBI system to handle this motor without spending $1000+ just on the injection system.
10-20-2003, 06:20 AM
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Depends on what "a nice set of pistons" is.
Looks to me like the best thing to do would be to buy pistons for the 511 block and just build it.
Ditch the 882 heads, anything you do with them will be a disappointment. Power lives in the heads. Nothing else you can do will make any difference if you run those 165 HP 350 / 175 HP 400 70s smogger heads. HP = flow, pure and simple; since power comes from burning gasoline molecules which require air to burn, and since each molecule contributes some energy, and since HP = energy per unit time and flow = molecules per unit time, they are direct equivalents.
I have a friend who thought TBI was a great idea, after he had had a TPI Vette for a few years and discovered how limited that was; so he got a TBI truck, put an otherwise pretty nice 400 in it, and got one of those Holley 4-barrel TBIs with the Chrysler injectors. I don't think that truck ever ran right; maybe once, late in its life, for about 10 minutes, before an injector failed or a plug fouled or some other stupid thing happened to it. He tried getting chips burned for it, at least 12 that I can remember. He finally bought a Haltech and that was when he finally got it to run right .... once. After about 5 years of frustration he finally gave up and bought an Accel ProRam. The Haltech made that easy to get running right. He immediately began twisting off axles, going through transmissions, etc; you could tell it worked a whole lot better. All of a sudden the truck made power with no other changes besides getting rid of the TBI.
There's nothing about TBI that requires a roller cam. That notion is just plain wrong. But if you've been reading it on the TBI board, there's no telling what misinformation you might have come across, posted by no telling how inexperienced a person. But you would be wise not to even go down that straight road to $$$disappointment$$$. A roller setup will cost about $600, and will only perform marginally better than a flat tappet, if at all, in a typical street build. Put your money into heads and an alternate induction system, where it will do some good.
Looks to me like the best thing to do would be to buy pistons for the 511 block and just build it.
Ditch the 882 heads, anything you do with them will be a disappointment. Power lives in the heads. Nothing else you can do will make any difference if you run those 165 HP 350 / 175 HP 400 70s smogger heads. HP = flow, pure and simple; since power comes from burning gasoline molecules which require air to burn, and since each molecule contributes some energy, and since HP = energy per unit time and flow = molecules per unit time, they are direct equivalents.
I have a friend who thought TBI was a great idea, after he had had a TPI Vette for a few years and discovered how limited that was; so he got a TBI truck, put an otherwise pretty nice 400 in it, and got one of those Holley 4-barrel TBIs with the Chrysler injectors. I don't think that truck ever ran right; maybe once, late in its life, for about 10 minutes, before an injector failed or a plug fouled or some other stupid thing happened to it. He tried getting chips burned for it, at least 12 that I can remember. He finally bought a Haltech and that was when he finally got it to run right .... once. After about 5 years of frustration he finally gave up and bought an Accel ProRam. The Haltech made that easy to get running right. He immediately began twisting off axles, going through transmissions, etc; you could tell it worked a whole lot better. All of a sudden the truck made power with no other changes besides getting rid of the TBI.
There's nothing about TBI that requires a roller cam. That notion is just plain wrong. But if you've been reading it on the TBI board, there's no telling what misinformation you might have come across, posted by no telling how inexperienced a person. But you would be wise not to even go down that straight road to $$$disappointment$$$. A roller setup will cost about $600, and will only perform marginally better than a flat tappet, if at all, in a typical street build. Put your money into heads and an alternate induction system, where it will do some good.
10-20-2003, 07:06 AM
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Originally posted by RB83L69
I have a friend who thought TBI was a great idea, after he had had a TPI Vette for a few years and discovered how limited that was; so he got a TBI truck, put an otherwise pretty nice 400 in it, and got one of those Holley 4-barrel TBIs with the Chrysler injectors. I don't think that truck ever ran right; maybe once, late in its life, for about 10 minutes, before an injector failed or a plug fouled or some other stupid thing happened to it. He tried getting chips burned for it, at least 12 that I can remember. He finally bought a Haltech and that was when he finally got it to run right .... once. After about 5 years of frustration he finally gave up and bought an Accel ProRam. The Haltech made that easy to get running right. He immediately began twisting off axles, going through transmissions, etc; you could tell it worked a whole lot better. All of a sudden the truck made power with no other changes besides getting rid of the TBI.
There's nothing about TBI that requires a roller cam. That notion is just plain wrong. But if you've been reading it on the TBI board, there's no telling what misinformation you might have come across, posted by no telling how inexperienced a person. But you would be wise not to even go down that straight road to $$$disappointment$$$. A roller setup will cost about $600, and will only perform marginally better than a flat tappet, if at all, in a typical street build. Put your money into heads and an alternate induction system, where it will do some good.
I have a friend who thought TBI was a great idea, after he had had a TPI Vette for a few years and discovered how limited that was; so he got a TBI truck, put an otherwise pretty nice 400 in it, and got one of those Holley 4-barrel TBIs with the Chrysler injectors. I don't think that truck ever ran right; maybe once, late in its life, for about 10 minutes, before an injector failed or a plug fouled or some other stupid thing happened to it. He tried getting chips burned for it, at least 12 that I can remember. He finally bought a Haltech and that was when he finally got it to run right .... once. After about 5 years of frustration he finally gave up and bought an Accel ProRam. The Haltech made that easy to get running right. He immediately began twisting off axles, going through transmissions, etc; you could tell it worked a whole lot better. All of a sudden the truck made power with no other changes besides getting rid of the TBI.
There's nothing about TBI that requires a roller cam. That notion is just plain wrong. But if you've been reading it on the TBI board, there's no telling what misinformation you might have come across, posted by no telling how inexperienced a person. But you would be wise not to even go down that straight road to $$$disappointment$$$. A roller setup will cost about $600, and will only perform marginally better than a flat tappet, if at all, in a typical street build. Put your money into heads and an alternate induction system, where it will do some good.
Holley has since changed to Delphi injectors and the units work well. They are a reliable injector with the correct spray pattern.
This is also true of the OEM Rochester injectors that come with the GM TBI units. A good injector that works well.
If anyone is looking to purchase a used Holley TBI avoid the units with the black hemispherical caps over the injectors. The Delphi injectors have no caps and the connector exits at a right angle. Make sure this is the unit you purchase.
RBob.
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10-20-2003, 10:45 AM
#8
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Holley has since changed to Delphi injectors
Now, if they can fix some of the other things that were wrong with it; bad castings (his leaked from the FPR chamber into the back 2 barrels); air cleaner stud that breaks off (his did that, and fortunately got lodged in an intake valve and hung it open, and so didn't hurt anything); wiring that doesn't match the stock plugs; etc. etc.
10-20-2003, 12:38 PM
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Engine: Boosted LSX
Deff get some nice heads. 4xx's can use the air and cam.
Im building a
418now.
AFR195's
HSR
Eagle Crank and Rods
SRP pistons.
Solid Roller Cam conversion
This is going in my 91Vert
Im building a
418now.
AFR195's
HSR
Eagle Crank and Rods
SRP pistons.
Solid Roller Cam conversion
This is going in my 91Vert
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