KCS

iTrader: (20)

Not really, not in my opinion.

From a performance standpoint, with the small displacement 5.3L, I think you'll benefit more from the increase in torque from the higher compression ratio thanks to the smaller chambers. The 243 heads do have a flow advantage, but I don't think it will be worth much with a stock LS1 cam like what you're planning to run.

A "performance" valve job and milling shouldn't be much more than $250. You could easily sell the 243 heads for more than that to offset the costs or you could probably even buy aftermarket 2.02" intake valves and break even. Then you have a freshly machined set of heads to go on your engine with wear and tear from mileage essentially back to zero.

On the other hand, if you mill the 243 heads it might cost about $75-$100 and you might be able to sell the 862 heads for that so you could still break even. The main difference is that you would be using the 243 heads that still have the old stock valve job which may or may not seal very well and less PTV if you ever decided to put in a larger camshaft.

TrickFlowTech

I don't know about your budget but our 205 heads fit that bore and has 58cc chambers and 2.000 intake valves. They make great power. The part number for them is TFS-30510001-C00. Let me know if you have any further questions.

A.R. Shale Targa

iTrader: (2)

I talk these up ALL THE TIME
flow 300 cfm past the 2.00" valve, have better than stock piston to valve clearance due to the rolled over 13.5 degree valve angle, AND have the powdered metal guides in them which makes them stock rocker arm compatible