What do you want out of your swap? A good daily driver, street/race truck/ all of the above?

Sounds like you have a good start. Do you have hp goals?

Do
1. Buy a CPW harness
2. Buy a Holley pan.
3. Buy used when you can
4. Cam, I would suggest around a .220-.224 duration just under .600 lift, and 112 or so for the idle you want w/ comp 918 spring
5. Dual 2 1/2" exhaust (IMO)

243 heads work great, mill them down to get your compression back up, but you can make over 300 RWHP with the 5.3 with stock heads and the right cam. Mine put down 313 on a 1 pull tune (long story)

Plan, plan, plan, and research, research, research.....Glad your here. Were all here to help!

 

thanks for your reply Iroc-10

well, my goal is to have a respectable running truck....not looking to run 10's...maybe somewhere in the mid 12's. want a great sounding but well working camshaft. want a clean, not cobbled factory looking install. Not a drive every day truck, mostly a weekender, but something I can take on weekend trips to some of the non local cruise in's. Would like to see 300-350 RWHP.

what are the 243 heads normally found on?? will they work with the factory truck intake?

thanks!!

 

243 heads are found on newer 5.3 trucks (l33 I think) and cars (impala ss, Monte Carlo ss, etc.), ls6 corvette and camaros for sure. All are not the same however but only have slight differences that I am aware of. The first being lightweight valves in the corvette version but they are also a bit longer to make up for camshaft lift differences if I remember correctly. IMO, the lightweight valves are a bit scary if going with a high lift cam but that's another story. All the other 243 heads have regular valves which are heavier. 799 heads are the same as regular 243 but have a little rougher casting. I have heard of some truck engines having one 243 on one side and a 799 on the other but who knows. My personal experience is with 317s and 799s. They seem to work well with the stock valves, retainers, seals, locks, and PAC racing springs installed. I have never been on the dyno but with a 4100 pound blazer running mid to high twelves I think I am around your goal area with just a smallish cam. Your plan and iroc10 suggestion is totally feasible and cost effective with everyone falling in love with ls3 heads nowadays (for good reason). Sorry for the novel, just like to share info so that others can expand and have a better idea of what they do or don't want to do.

 

Thanks a bunch, was thinking that the 243 heads were only corvette but will definitely keep my eyes open for a set now....maybe some port work and larger valves to wake them up. Since the engines are pretty tuff I'm also thinking about a small shot of N2O for grins and giggles.

I have read the sticky on the oil pans but didn't see the Holley pan in there. Anyone have a build thread using one? Do these pans fit without cutting the cross member?? how about ground clearance? I really like the thoughts of a factory made cast pan vs a welded sheet aluminum or modified cut down cast one.

 

Plan on cutting the crossmember, period. SOMETIMES things can work without cutting, but your just going to F yourself if you don't cut it. I used the Holley pan. It's in my build thread. It works great on lowered trucks, and you NEVER have to worry about smacking it on a parking block, or a bad road or whatever.

 

Yea, look for 799/243 heads. Don't worry about find the light weight valves. You'll pay too much for them when the regular stuff will work fin for your plan. Cpw poly mounts and harness, Racing innovations stainless shorties, ls7 lifters, arp rod bolts for your stock rods... Check ls1tech classifieds for the heads and other engine parts.

 

I was just thumbing thru the new jegs and they have the oil pan for $135 free shipping.
Alot cheaper than I paid for mine.

Rod bolts for sure since its a 99. Older ones are supposedly weaker. And you'll have the pan/windage tray off anyway.

 

now with older SBC engines, when replacing the rod bolts, the rods needed to be resized for proper cap alignment...of course that was actually a stud and nut set-up. With the PM rods using capscrews is alignment still and issue??

 

With the PM rods using capscrews is alignment still and issue??

That's an ongoing debate, some say yes and others say no. There's even a company that makes bolts that are supposed to not need the rods resized.

You could always check though, especially if you change the heads lol

 

There are several oil pans that work.
Review the sticky at the top of this section.

The Holley pan is great. It runs around $400 at Jegs
The H3 Alpha pan is the next best thing. Is a little lower, but averages around $160.
Other pans have been used too.

 

Got my H3 pan thru jegs $133. Sold as the muscle car pan. Comes with everything.

 

The H3 and the Muscle Car pan are the same animal?!? Let me know, please. I already have an H3 pan and negotiating on a muscle car pan at the moment.

 

I like the H3 pan price however the amount of "hang down" below the cross member concerns me. Just by crawling around under my s10 I can see that my cross member and exhaust cross over pipe have took a few shots from road debris, speed breakers etc. With my truck being lowered Id like to keep it even with the cross member at least.

Any off road companies make oil pan skid plates for LS engines?? guess I could fab my own and weld it to the x member.

has anyone used the Holley accessory brackets yet?

 

I just picked one up for my swap. I will be running vette accesories, so I got the Holley R4 compressor bracket and the shortest spacer. No fitment info on it yet.

 

The (hummer) H3 pan is the exact same as the "Muscle Car Pan". It's also known as the LH8 pan. The LH8 is the RPO code for the 5.3 engine that was offered in the Hummer H3 and Chevy Colorado. All the exact same part.

 

Yep