Hi all , sorry to ask this question as its prob been asked many times .

im from the uk and im going to be doing a top end rebuild on my 2001 5.3 chevy tahoe , really dont know where to start i want to upgrade the heads so is it a good idea buy new performance heads or just upgrade all the springs and evey thing in the stock heads .

i also want a nice sounding cam to go with the heads i already have some long tubes that are waiting to be fitted . my tahoe runs on LPG fuel so i need hardend valves and seats .

over here its hard to get some good advice and where to go so really any help to steer me in the right direction would be great . thanks

 

Whats your budget?
Is emissions and tuning going to an issue for you in the UK?

 

budget not to over the top lol

emissions is not a problem as it runs on lpg i have already removed the cats , tunning is ok also

 

243 heads milled .030 of an inch (.762 mm) to retain current compression with hardened valves and seats. Use the 243 springs as is with a 212/218 low lift comp cam. This is a proven combination for petroleum engines, I don't know if an LPG fueled engine would react the same.

 

ok ill look into it , am i going to be able to do a topend rebuild ok without touching the trans ?

 

I would look into getting an external tranny cooler, and start saving back for some transmission upgrades. The cooler temps will help the transmission out. You can leave the trans stock for now, and shouldn't have any problems depending on what the life of the transmission has been up to this point, just keep in the back of your mind, anytime you add power, you are putting more stress on the drivetrain, and at some point, you will find your weak link.

The cam that I threw out there plays well with the stock stall, even on something as heavy as a Tahoe. It will leave some power on the table in the higher RPMS vs. something like a 220/220 duration cam, but you keep and possibly add a little bit of low end grunt that helps get our heavy trucks moving.

 

well today i took one of the heads off that was giving me trouble and im shocked to what i saw im gutted

take a look

cylinder 2



cylinder 4 you can just see the crack



cylinder 6 same again



cylinder 8 o dear where the ally go



now i know theres risks of running lpg fuel as its burns at 110 octane and its gets hot that leads to problems but come on . ive still got to take drivers side head off in the morning

now you can see why i want to uprade my heads and every thing lol i havent a clue where to start now . im gutted

 

Were these the stock valves or hardened?

 

thay are ment to be hardend valves and seats the last owner had it built 4 years ago who ever built it needs a slap because i dont think any of it is hardend is there any way for me to tell ?

 

The number of people on here that has experience bulding LPG engines is probably almost nil. I'm one of those with no experience. But, the strongest valves I know about for hardcore racing are titanium valves. I suspect you were running a little lean, but I have no clue about LPG tuning.