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Lets cobble some junk together and make my daily more fun!
I daily drive a 99 Trans Am, has pretty high milage but has been very dependable. It has reached 265K miles, still runs and drives just fine but can tell it's getting tired, and I'm ready to spice it up some. I have acquired a few project engines over the years and hoping to make something kind of cool from a pile of junk. 1st goal dependability/drivability. 2nd goal 450-500 HP. 3rd goal budget, keeping it cheap would be great, but 6,000 is the Max. Reason for this is drivetrain drops outs from Hawks Motorsports, LS2 Engine/4L65E Transmission for around 10K, figured 6K for engine 4K for transmission. Lets get started!
-Current Mods- SLP Flow Pack, MagnaFlow catback, EGR delete, UMI lowering springs, KONI orange shocks, UMI rear LCA and PHB. Transmission-4L60E Rear End- 10 bolt 2.73 Yes rear end and trans will be addressed on a separate budget, but general input is appreciated.
-Current Junk pile- Gen 3, 5.3 and 6.0 cast iron. 706 heads and 317 heads. Cam Engine Pro Performance MC315944- Dur@.50" Int Exh:218 227, Valve lift Int Exh: .523 .524, Lobe Sep Int Exh: 109 115
The 6.0 is one of the odd ***** with long crank, figured putting new rotating assembly and doing stroker..not 408 because I hear this beats up piston skirts but the 397 I think? Obviously this would take up half of the engine budget, so remaining funds would be buttoning everything up. Also not opposed to bumping compression and running 93 octane.
Added PFA
Yes LS1 with 853 heads. If anything is reused will need to freshen up. Currently runs good, good oil pressure, but drinks and smokes more than I ever have along with piston slap and lifter tick.
If we’re talking about a strictly parts on hand type build, obviously the 6.0 with the 706 heads would be the one to build. This will assume you have a decent machine shop to work with that isn’t gonna kill the plan on labor. It’s very easy to end up higher in cost than your other plan of just getting a decent dropout.
Either the 5.7’s or the 5.3’s crank will work fine for this type build. Hell, the turbo guys run them well past what traditional thinking will tell you is safe. As long as the piston rod combo is same or lighter weight, They will just end up with some deeper balance holes drilled in them. Which is the cheapest way to balance. Speaking of… that whole budget thing again…
gen iv rods and pistons are cheap takeouts, and will work fine for the goal your targeting. If the bore on the 6.0 is shot, sending these out to get the skirts recoated will be about $250. This will allow you to clean up the bore on the 6.0, but still use the smaller pistons.
The other option here would be 6.2 rods and pistons and just opening up the block to 4.065”.
the cam you have will work. Same as anything else, something else could be better, but if we’re keeping a budget…
heads will be where this thing can make or break the deal. If you’re comfortable swinging a die grinder yourself, you can save some serious coin here. Take the 2” intake valves from the 317’s, and have the 706’s seats opened up for them. A good multi angle valve job is critical here. The rest of the porting is straightforward, and there’s actually a lot of pics/guides out there on what to do/not to do. The headache is making sure you keep each cyl same same, and the time to do it. Spends a bit of money here might be wise if you’re not comfortable doing all this. Someone like total engine airflow has a great rep for doing all that work, although I’m not sure what the pricing is these days.
the reason I stressed budget several times here is with the age of the car and the miles on it, you can be all but guaranteed that there’s something else needing attention once it’s opened up in there. Some people are more risk adverse here than others. I.e. reusing certain gaskets, sensors, hoses, etc.
the 6.0 with that cam, and good ported 706’s would easily meet your hp goal.
The 853 heads might be better on a stroker. They have larger valves and I think slightly larger ports. Compression ration will be reduced by about .5 point or so.
Thanks for the input, I'm pretty new to the LS platform at far as internals go. Did not know cranks interchange like that, was the only reason I was looking at stroking the 6.0. Like you said the machine shop will probably make or break the budget for getting heads worked. Also supporting mods will take a chunk, injectors, intake, will probably be putting LT headers in while I'm there.
Use the 6.0 with the 706 head to bump compression up. I'm fairly certain Richard Holdener tested 317 vs 706 vs 241/853 heads on a 6.0 one time and the 706 heads outperformed both from top to bottom. Hop on Youtube and have a look for his video.
Still planning on going through with engine work, funds have been tied up in cosmetic work. Car was hit back in June last year at work, finally all the pieces are coming together though. Installed some SLP goodies I've hoarded over the years SLP HO hood and SLP IROC spoiler, went for all over paint job and paid the difference out of pocket. Figured I would share the eye candy here because, well I don't really know where to post it lol. Enjoy!
11-10-2023, 08:44 PM
Lets cobble some junk together and make my daily more fun! 
