aluminum heads with stock throttle body?

[slimtastic]

im planning on dropping a set of aluminum GN1's/harland sharps and a port matched lower intake, do you think a dead stock throttle body/ upper is gonna hold the combo back or should i invest the half grand on a 70millimeter tb and precision upper with rjc plate? my redline is 5600 and the tranny shifts at 5200.

thoughts?

 

[HOT ROD-GN]

im planning on dropping a set of aluminum GN1's/harland sharps and a port matched lower intake, do you think a dead stock throttle body/ upper is gonna hold the combo back or should i invest the half grand on a 70millimeter tb and precision upper with rjc plate? my redline is 5600 and the tranny shifts at 5200.

thoughts?

what your combo?

 

[bad V6]

There are individuals on this board that have been in the 9's with a stock throttle body. I would be to spend the money somewhere else.

 

[slimtastic]

212/212 cam, 6262billet, bs3, 120lbs, custom frontmount. stock manifolds. going for big hp on street gas and thus far on stock heads have gotten 402 hp on a dynojet

 

[bison]

Your shift rpm should be around 5500@26-27psi. It should pull past that in 3rd even if you have a really good converter. The car should run 10.50 fairly easily at that boost pressure and 23-24* advance. If you went to 30psi you could get away shifting at 5600-5700. You will want the converter flash to 5100. If you can get all that together with the tune it will run the number. Btw the heads have no effect on throttle body requirement unless the heads are directly increasing rpm. At 5500 on a 231 the stock one isn't hurting anything. Your trans shifting at 5200 is hurting you a little

 

[jmccurdy]

I have GN 1s on my car with a stock throttle body, no issues

 

[slimtastic]

i guess what i mean to ask is if anyone has switched from a stock throttle boody to a bigger unit and noticed a difference in hp or quarter times....all this with a combo that includes GN1 heads.

 

[bison]

i guess what i mean to ask is if anyone has switched from a stock throttle boody to a bigger unit and noticed a difference in hp or quarter times....all this with a combo that includes GN1 heads.

This is an open ended question. If I put a stock throttle body on an engine that makes power to 6800 with GN1 heads it would drop some power. If i put GN1 heads on an engine with a small cam and the engine made peak power at 5100 or so i dont see the need for a larger throttle body since it would likely not be and shouldnt be going much over 5500. The heads used dont determine the throttle body needed. Most wont see anything from a throttle body since their trans will be shifting not much over 5000 and they run small cams and the engine wont make enough power to pull over 5500 if they have a good converter in it.

 

[L8TRH8R]

The difference you'd notice would be in your tip in throttle response, other then that, like Bison said you'll have to be over 5600 to really SEE a difference. There was a large difference with throttle response though for me.