Help me build my 5.3 Vortec

[DavidBoren]

I really was hoping to not be confusing, and I apologize if I wasn't clear. The OP stated that a cam swap is in the plans, and I am under the impression that all 4.8/5.3 engines have vvt.

I would absolutely keep it. Hell, I would add it if it didn't.

Run an electric water pump and you don't have to worry about the vvt timing cover working with your front accessory drive.

[DavidBoren]

The aggressive vvt cam from comp cams is a beast of a cam, with an advertised operating range of 2000-7100rpms.

Dur. advertised (I/E): 275/289
Dur. @ .050" (I/E): 222/236
LSA: 114
Lift w/1.7 (I/E): .566/.573
Just for fun...
Lift with slp 1.85 rockers (I/E): .611/.629

Throw 20 degrees of cam phasing on top of that and you have yourself a performer. I'm sure the Texas speed and mast vvt cams are comparable (probably better, even), but you get the point.

With comp cams ramp rates, I bet the 1.85 rockers would be a destroyer of valve springs, and .629" of exhaust valve lift probably introduces the valve to the piston, in the worst kind of way. So be careful to check for ptv clearance, and get damn good springs if you want to run 1.8 rockers.

With stock 1.7 ratio rockers, you shouldn't have any ptv clearance issues (but always check). And 1.7 rockers will play nicer with valve springs.

This is obviously the upper end of what is available for the vvt cam in the aftermarket. You can find more civilized vvt cams. Mast or Texas speed may even offer more aggressive vvt cams.

The comp cams information was readily available, and I wanted to show you what's out there.

Some custom fly cut pistons, that aggressive vvt cam, the slp 1.85 rockers, and some Pac gold valve springs would make for one angry little 327...

[JsTA]

Originally Posted by DavidBoren

I really was hoping to not be confusing, and I apologize if I wasn't clear. The OP stated that a cam swap is in the plans, and I am under the impression that all 4.8/5.3 engines have vvt.

I would absolutely keep it. Hell, I would add it if it didn't.

Run an electric water pump and you don't have to worry about the vvt timing cover working with your front accessory drive.

Most 4.8 and 5.3 engines did not have VVT. That wasn't introduced until later in the Gen IV production run (2007ish or so I believe) so he won't have to worry about that if he got a 99-04 engine.

OP what year engine did you get?

[Paraman1]

Its an 02 out of a Tahoe . I picked up some 243 heads with the trunnion upgrade and springs that are good to .660 lift (I believe they are Texas Speed) .

[JsTA]

Originally Posted by Paraman1

Its an 02 out of a Tahoe . I picked up some 243 heads with the trunnion upgrade and springs that are good to .660 lift (I believe they are Texas Speed) .

Then you are good, that engine doesn't have VVT or AFM. Like others have said I would get those 243 heads decked and then make sure whatever cam you go with will not cause any piston to valve clearance issues (which you shouldn't because of the slightly dished pistons).

[WSSix]

Paraman, as a point of reference, I built an early 5.3, 2001 if memory serves me well, that used mildly ported LS6/243 heads, LS6 intake, headers, and a small cam similar to what hifi utilized in his build. The car put 350hp and 350tq to the rear wheels through a 5 speed. The torque curve was ridiculously flat and broad. The engine sounded great at idle and drove even better. Point being, these are great engines that perform really well with simple modifications. You're on the right track. Don't over complicate this and you'll have a great engine on your hands. Good luck!

[BowtieGent]

Originally Posted by JsTA

Then you are good, that engine doesn't have VVT or AFM. Like others have said I would get those 243 heads decked and then make sure whatever cam you go with will not cause any piston to valve clearance issues (which you shouldn't because of the slightly dished pistons).

Out of curiosity, how much material are we talking about having removed, assuming these are virgin heads that haven't been decked previously?