Looking for a cam recommendation for my genIII 4.8.

.030 overbore. So that I think puts it at about 298c.i.

862 heads (thinking about milling and playing around with gasket thickness to get compression to around 10:1)

shorty headers(1&5/8� primaries I think)

Vararam ram cold air kit

FTI 2600 stall

3:42 gears

Will have the vehicle street tuned by vengeance racing.

Looking to improve low and midrange performance mainly.
Truck will be a daily driver, no towing.
Some chop would be cool but that�s not high priority.

Thanks,
David

 

Take about .015 off the head and use a.040 (for good quench) head gasket to get about 10:1 compression.
Get a good truck cam with about 212/218 duration, .550/.550 lift, and about 115 LSA. Slight chop.

 

I would also suggest a cam with 212/218 duration since you have a stall. If you had no stall a cam with 206/212 duration @ .050 would work well.

 

Hey there, the SUM-8719 209/217 112 +1 .545/.545 would be a nice match for certain. Works with our LS6 springs to extend the rpm range. It does tow well when you need to. You will hear the cam and a lot of that is up to you and where you want to set the idle speed. 650 rpm and it's going to have a nice steady lope. We agree wacking the heads ,030 is a good move to bump compression. TEA does a competition valve job and mill job very inexpensively. It actually runs very close to some ported heads because of what they do in the throat and their proprietary angles. You'll be surprised how inexpensive it is for the quality work and the gains.

 

If you want low and midrange I'd stay at a 210 or so intake duration cam, and I would do long tubes, they work far better for low and midrange than shorties.

 

Thank you all for your input.

So, I got 4 cams picked out based on y�all�s suggestions.

TSP stage 2 low lift:
212/218 .550/.550 112 or 114 LSA option

BTR stage 2 v1:
212/218 .553/.553 113+2

BTR stage 2 v2:
212/218 .553/.553 111 lsa

comp:
212/218 .558/.563 115+2

Im kinda leaning towards the Texas Speed cam with the 114lsa,
but would the additional lift or ground in advance of the others be of much if any benefit?

 

Research those cams and the SUM-8719 to get an idea of what you want. Look for things such as rpm range, intake open and close, exhaust open and close so you can have a better idea of what you are looking at for cams.

 

I like the btr stage 2, 111lsa out ove your picks. It should feel (punchey) for lack of better words. But I'm weird like that. Did a tsp 228r on 110 in a lq4 pulling truck and it had massive mid range, excellent street manners. I wouldn't be afraid to do a tsp 224 cut on 111 or 112 for your truck. I'm nuts so don't take me to serious.......

 

Yeah... like you're so alone on that count.... LOL

 

I'd do the btr stage 2 for the 111 lsa out of that list.

 

Just to clarify, this long block is already together?

If not, I would highly recommend swapping out the 4.8 short block for a 5.3 short block instead of boring out the 4.8.

 

One thing to consider is that you need to check the compression height of the replacement piston in relation to the deck. They usually reduce the compression height to maintain a factory compression ratio and also to allow for deck resurfacing.

With a 0 deck, a .040 gasket, and a minimal clean up on the heads, you would be right a 10:1.1\

https://www.summitracing.com/newsand...ion-calculator

 

The motor is still in service in the truck with
343k miles on it. I�m shooting to start my build late summer of 2021 so I�m doing as much homework as I can in the meantime.

I�m wanting to use speed pro pistons that list the CD @ 1.324. Which I think is close to what the stock pistons are. Hoping to get away with minimal resurfacing on the block, but won�t know until a machine shop looks at it.
Mahle makes a piston set with 1.313 CD.

Being I have early 862 heads, they more likely than not have the notch on the sealing surface.
I think it�s WS6store.com that makes some LMS gaskets in .040 that will work with the notch or Mahle makes some that will but they�re .051.

 

If its still in the truck, I would just go ahead and make the leap to a 5.3.
It'll make more torque than the mods you're planning.

 

To go 5.3 all I would have to do is source the 3.622 crank and the shorter rods, stay with the flat top pistons and that would get me in my target compression ratio.
Something I�ll definitely consider.

 

If it's going to the machine shop and getting work anyway, and your buying some internals, have you thought about making it a (iron 5.7) . Just a thought. Now that I read back, is it a iron block ?

 

It is a iron block.
Will the 862 head work with the larger bore of 5.7?

 

Here's what I would do. Sell the 4.8 and put part of the money you were going to use to build up the 4.8, and use it to just buy a 6.0. Then use the rest of the money you were going to put into the 4.8 to bore it, pistons, all the machine work and use that to freshen up the 6.0, or if you find a good enough 6.0 you can drop it right in. Or pull it down put new gaskets, mill the heads, or put some cheapy 706 or 862 heads on it. (there's a lot of ways to have a much better outcome and spend similar money to building up the 4.8 the way you're talking about doing it)

You'll have more power than that bored 4.8 will ever make, and spend the same or less money, and still have a fresh motor in the end.


You want more low and midrange, that was your goal. Really what you're after is torque, trying to increase torque on a tiny motor in a heavy vehicle is just two wrongs that don't make a right. And I PROMISE you, you will be far happier with a stock 6.0 than you will with a cammed 4.8

And you can always cam the 6.0, or mill the heads and slap em back on. And then you'll really be happy.

 

I'm not a head guru, but I don't see why not. Personally id try to find some cheap 799 heads my 4.8 has em, my old ls2 6.0 had em... Summit racing has piston/rod combos that would work with a 3.905 bore and 5.3 crank. If your going to machine it any way that's what I'd do. But I get it you could put it together for cheaper with used parts and attention to detail......
(Oopooterss) post above is a better plan than mine. Prolly cheaper in the long run with good results.