Zac2003

I am doing a stock bottom end rebuild and going back with stock pistons and I have an 01 ls1 I would like to get a set of 862 5.3 heads and have my valves from my 241 put in the 5.3 heads but since its a smaller combustion chamber will I have piston to valve issues I know I didnt with the 241's but I have searched and have not found the answer?

tsunami cam specs are 235/240 .648"/.609 111 lsa

Thanks in advance

Canbarelygo

what up zac i wondered what was up with your car. ive got the ls1 valves from my ls1 heads in my 5.3 heads but im not cammed lol but people run ms4's with tsp 5.3 heads so i dont see why youd have any trouble at all unless the heads have been milled the only thing the combustion chamber should effect is the compression.

Zac2003

well if the ms4 clears then the tsunami should hmmmm what did it cost to get your bigger valves put in?

Zac2003

looks like alot of people with ms4 have to flycut the pistons....

Canbarelygo

well as far as fly cuttin alot of people mill heads as well or have the cam degreed different and the ms4 also has more duration.

i bought my heads and had my valves and everything swapped from my ls1 heads into my 5.3 heads for 350 which includes buyin them and i kept my ls1 heads. id give dougs shop a call see what Dale would do them for he did everything for me i dont see why he'd charge anymore than what a valvejob would cost. i think youll have to buy valvestem seals but theyre cheap and its smart to do anyway.

have the heads been milled at all? and honestly man if it would give you piece of mind do some measuring and checking clearances to be positive but i dont see you havin a problem.

Cosmos

iTrader: (15)

Thats ONLY if the heads have been set up for that by TSP or another shop.

Canbarelygo

so your tellin me with unmilled 5.3 heads youd need to flycut? and what the hell do you mean setup they use gm cores? im sure if someone tells tsp about what cam theyre gonna do im sure they can mill appropriately to avoid flycutting but why would a run of the mill set of 862s have any more clearance issues than an ls1 head?

Cosmos

iTrader: (15)

They recess the valves for more PTV.



Call TSP tomorrow and talk with them about your set up.

Canbarelygo

so all the cars with ms4s and stock ls1 heads also have recessed valves. intense.

Cosmos

iTrader: (15)

Stock 5.3s have less PTV on a stock ls1 short block than stock Ls1 heads do.

Canbarelygo

educate me how do they have less ptv because short of the combustion chambers appearing very slightly smaller my unmilled 5.3s looked dimensionally identical to my 5.7s side by side but i may be wrong

Zac2003

called tsp today and they talked like as long as the heads have not been milled that I won't have any ptv issues.....

Jason 98 TA

iTrader: (4)

All depends on who sets up the heads. The valve locations will determine the p/v. If we do the cnc work we setup the valves & milling specific to the application. Without doing the CNC work I wouldnt run 5.3l heads, the chambers are small.