LT4 heads
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
LT4 heads
here is a question that is somewhat relavant....
Ive heard quite a few times that the stock LT4 heads were designed very very well. so well in fact that if you get stage 3 port and polish professionally done on them there isnt many better flowing aftermarket heads.
is this true? what about the AFR 220s? do those flow better than P&P LT$ heads? what if you had the 220s P&P?
i am obviously talking about very high naturally aspirated horsepower applications here where you need as much airflow as at all possible. thanks for the help.
Ive heard quite a few times that the stock LT4 heads were designed very very well. so well in fact that if you get stage 3 port and polish professionally done on them there isnt many better flowing aftermarket heads.
is this true? what about the AFR 220s? do those flow better than P&P LT$ heads? what if you had the 220s P&P?
i am obviously talking about very high naturally aspirated horsepower applications here where you need as much airflow as at all possible. thanks for the help.
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
The AFR 220's will outflow a set of LT1 heads on the top hands down but the motor will suffer down low. The AFR 195's would be a better comparison to the GM LT4 heads if you want a direct comparison. The Big difference if you sent both sets of heads out to get them worked would be the amount of material on the AFR head.
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
so if you had a set of 220s ported and polished and a set of LT4 heads ported and polished then you would get more flow and thus more power out of the 220s? as well as have more material allowing better strength for say NOS?
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Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
after looking at AFRs website looks like P&P 227s flow about the same as very well P&P LT4 heads. maybe a little bit better. i guess the only difference is the fact they are a lot stronger for conditions such as nitrous?
Race Director
Joined: Feb 2003
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From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
The LT-4 head is a very good GM casting, but there are other aftermarket heads that are superior. Popular Hotrodding this month did an LT-1 build up and used Edelbrock heads - they got better HP out of the Edelbrocks than LT-4. Granted some will argue the "paid advertisement" aspect of feature articles, but numbers are numbers.
Also, keep in mind, that flow numbers are only a piece of the equation. They must be perfectly matched to the rest of the combination. Velocity in the port is as important too, especially in making torque.
If you are talking about starting with a set of 220 CFM runner cylinder heads and then porting them, you are looking at needing well over .600 lift to really be able to use the flow and you better be building a higher RPM motor. Otherwise, look at a smaller runner, but superior design, to make your power in a range you can use.
Also, keep in mind, that flow numbers are only a piece of the equation. They must be perfectly matched to the rest of the combination. Velocity in the port is as important too, especially in making torque.
If you are talking about starting with a set of 220 CFM runner cylinder heads and then porting them, you are looking at needing well over .600 lift to really be able to use the flow and you better be building a higher RPM motor. Otherwise, look at a smaller runner, but superior design, to make your power in a range you can use.
Race Director
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From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
And always remember, the guy with the most power doesn't always win. It has to be made in an RPM range that the car can use. And in an RPM range where you intend to use the car.
Good luck!
Good luck!
Thread Starter
Melting Slicks
Joined: Dec 2001
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From: Gainesville Fl
this is very true. i wish i knew more. i have my goals of what i want my car to be able to do but i am going to keep them to myself for now untill i do some more homework. i would rather have a car that has only 389rwhp that can do the 1/4 in 9 seconds than a dyno queen *COUGH*SUPRA that can put down 800rwhp and still only get a 12 in the 1/4. i dont care about dynos, i care about times.
Race Director
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From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
Originally Posted by 1996man
this is very true. i wish i knew more. i have my goals of what i want my car to be able to do but i am going to keep them to myself for now untill i do some more homework. i would rather have a car that has only 389rwhp that can do the 1/4 in 9 seconds than a dyno queen *COUGH*SUPRA that can put down 800rwhp and still only get a 12 in the 1/4. i dont care about dynos, i care about times.
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
this is very true. i guess there is no way to not choose cam and heads at the same time. and ur right i will have a lot of homework to do with the drivetrain althoughi have a DANA44 so im not to worried
