I will shortly be building an lo5 and looking for input. This is a smog conversion to. I know the lo5 heads are crap and think I should replace those first. After the heads I would swap the cam. Next I might add a blower. Finally I might go to a 502 block if possible. I will add all the other external stuff also along the way. I hope to reach 600-650ft/lbs with a nice flat curve in the low rpms.

for the blower to be smog legal I think I need to stay away from the vortec heads.

Would you guys reccomend anything different?
Someone reccommended Air Flow Research heads.
btw this is for 6k lbs truck with 44" tires.


Charlo

 

With 44's sounds like you do some offroading. Hill climbing or just mudding?

With hill-climbing you should keep the intake runner volume down. Maybe around 170-180cc.

With mudding you should go around 190-200cc.

The camshaft selection is key in your case.

 

I do both. Mostly mud running and sand drag. I am not to worried about rock crawling, I cant imagine using half that power with out breaking something on the rocks.

I was under the impression that cam options were limited due to smog/knock sensors.


Charlo

 

Definitely go with a bigger intake runner volume if you are sand dragging and mudding.

The MAP sensor is the biggest problem with cam selection. I'm just thinking that you'll need to get a cam with enough low end grunt that it will be able to turn those 44's from off-idle. Maybe one with a shorter duration but with a lot of lift. Maybe get some 1.7 rocker arms.

 

Thats what im worried about. I have 4.56 gears right now and may go to 5.13s. I also do my the mud/sand in compound low which multiplys by 1.96.
But still I dont want to have to take a 30ft running start


Charlo

 

So does anyone have a reccomendation for heads?
World?
AFR?
Edelbrock?
GM?
brand x?

 

do a search, youll be able to find anything you need to know about 350 centerbolt heads. I know that the AFRs, Edelbrock Performer and Trick Flow Twisted Wedge heads are all CA smog legal.

 

My mistake. I thought the Lo5 was the TBI 454. I am looking for smog legal reccomendations on a TBI 454. And no a search only told me that the Lo5 heads were crappy. Thats why I posted the question. BTW the search doesnt seem to be working again.


Charlo