stock 243s increase?

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Jul 28, 2011 | 02:19 AM

#21

02TransAm/Batmobile

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Quote:

Originally Posted by JohnJanz@Texas-Speed

If you just bolt on stock 243s I would expect to pick up right about 15rwhp.

So 15hp by swapping to 243's. How much would we gain from doing a valve job and lapping the valves on the 243's in addition to the 15?

Jul 29, 2011 | 11:19 AM

#22

Sales4@Texas-Speed

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I wouldn't expect a valve job by itself to make much more then 4-5rwhp. Now if you port the heads at the same time and match the valve job to the port you are liable to pick up a decent amount more.

Aug 1, 2011 | 08:52 AM

#23

RoadconeTuning

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the guys around here seem to always pick up 25-30hp just swapping to a set of 243's and thats with a crappy LS6 intake.

Aug 1, 2011 | 11:21 AM

#24

Patrick G

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I see a consistent 25rwhp gain by adding LS6 heads if the vehicle has a 220 or larger cam. 15rwhp is too low of an estimate in my experience.

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Aug 1, 2011 | 02:37 PM

#25

FASTFATBOY

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Quote:

Originally Posted by Patrick G

I see a consistent 25rwhp gain by adding LS6 heads if the vehicle has a 220 or larger cam. 15rwhp is too low of an estimate in my experience.

Pat, if I had a car with a cam only thats already tuned, and drop on stock 243's is a tune required? Will the MAF take care of it? Cam is a 224/231 on a 112.

Will it be lean or rich?

I am about to put a cam only longblock with the ecm that goes with it, I have a set of 243's sitting here.

I am gonna HPDE this car should I put in Katech rod bolts.

Aug 1, 2011 | 03:33 PM

#26

*02WS6TURK*

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From: Oregon Grown

Quote:

Originally Posted by Patrick G

I see a consistent 25rwhp gain by adding LS6 heads if the vehicle has a 220 or larger cam. 15rwhp is too low of an estimate in my experience.

This has me looking for a untouched set now to put on my current set up.

Aug 1, 2011 | 03:49 PM

#27

Nitroused383

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A proper valve job on a set of 243's really help. There isn't too many people who I feel do a proper valve job though. Considering I made 444 rwhp 416 tq with unported 62cc 243's with a proper valve job and a 224 cam. I spent around 20 hours doing a "proper" valve job by hand. GM's valve job is a POS, not concentric at all, you should atleast lap the valves to get them to seal.

Than again I used a lot of attention to detail. Did things most guys don't, measured correct pushrod lenght, setup springs .050" from coil bind, measured PTV and actually degreed my cam in. Also correctly port matched my fast to my heads, some of the ports don't line up worth a **** but guys wouldn't know unless they actually took the fast apart and looked. Most guys just slap **** together and wonder why it is low on power. Must be a "low reading dyno" haha

Last edited by Nitroused383; Aug 1, 2011 at 03:55 PM.

Aug 1, 2011 | 04:48 PM

#28

Patrick G

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Quote:

Originally Posted by FASTFATBOY

The tune will be off some, but the MAF should compensate enough to run it. We find that the engine is now rich at lower rpm (less velocity compared to stock), but leaner up at higher rpm (more airflow over stock). The VE tables would need to be adjusted 5-8% down low and up high, but the MAF will take care of the fueling at higher rpm without much drama.

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