I am about to switch over to TPI, and I know the heads on the L03 suck, so are the LB9 different and if so how? I can pick these up real cheap, so buying new heads is out of the question for the 305. I am really concerned with flow, and that the LB9 heads are 58cc. Thanks

 

I don't think that has ever been truly resolved. I pulled a valve cover to check my head casting #, and it revealed the head to be a standard 87-92 305 head. I don't know if its a swirl port head like the L03 heads.... the 305 TPI doesn't really need the torque that the swirl port design generates, unlike the TBI 305. If I recall correctly, the swirl port design was also partly done for emissions purposes, I believe it helps yield a cleaner combustion than non-swirl heads. Still, they SUCK for performance and can't breath at high RPM.

You used to hear about guys pulling 'TPI heads' off of junkyard 305 TPI cars, and putting them on their 305 TBIs and feeling a difference. I haven't seen such claims in a while, though. They may well be the same head, both L03 and LB9. The LB9 does perform a lot better though, and responds better to mods, so I wouldn't be surprised if the head was a different, better flowing casting.

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

supposed 'peanut cammed' car (yeah, right)

Built on Wednesday

 

*BREAKING NEWS*

I got the casting # off of one of my heads.

14101081

also known as '081' heads

Pablo pulled the casting # off of one of the 305 TBI heads he has lying around.

14102187

'187' heads.

YES, there were two different heads, and the 305 TPI got the better ones. There's the proof. The TBI heads are the infamously hated 'swirl port' monstrosities.



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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

supposed 'peanut cammed' car (yeah, right)

Built on Wednesday

 

You da man I thought there might be a difference. Thanks for cross checking those numbers for me. Now I can get some extra performance without having to rob a bank.

You guys rule

 

Go pick up your car! I dont want to have to come pick your a$s up all the time. Blah blah blah. Got my exhaust stuff cut and hopefully I will have it on later. I am leaving early from work. do you have some clamps for 3". Oh by the way you cheap poor college punk, GET A JOB! Oh I mean just get some AFR's and be done with it already. Damn college kids always want more for less. Speed=$$$$.