I currently have a LM7 5.3
stock bottom end
862 heads
214/222 .550/.550 108 cam
1 3/4 longtube headers
50lb flex fuel injectors
cold air intake
3.43 stock gears

I recently picked up a pair of 799s heads that I’m going to send to get milled and ported by Texas speed , im thinking 60cc chambers and .040 head gaskets 2.02 1.57 valves

im also switching to a NNBS intake with a bigger throttle body 90mm

either 4.10/4.56 gears
the truck is a regular cab short bed Silverado on
265/40r22s

part of me wants to go bigger cam, either a:
228/232 .629/.600 108 or
228/232 585/.585 112
or to keep my valve train happy
228/232 .550/.550 110

I know the bigger the cam the less bottom end I’ll have
just wanting some guidance and advice if throwing on some ported and milled 799s , NNBS intake , 4.10/4.56 gears will wake up the current cam 214/222 .550 108 enough to not want a bigger cam later on

also noting that my end goal is a built 408 with a 2.3/2.9 whipple supercharger but this plan is for way in the future


appreciate the help thanks

 

Do you have a stock torque converter? Going to a bigger cam, you will need a higher stall speed.

What are you using the truck for?

 

You can put the supercharger on your current engine while you are saving up for a 408.

 

Then it doesn't affect The Now. At that time you'll be building a 408, not "throwing" things on a 5.3. In which case, all of that is just drivel and monkey-spank, Now. It isn't a factor in the decision at hand AT ALL. The only way it would be, is to the extent that EVERY PENNY you spend on this 5.3 that can't be DIRECTLY transferred over to a 408, simply delays your ability to reach your 408/blower goal. A detour. A diversion from the true path, chasing after shiny things.

OTOH if you wanted to put that on Now, which there's no particular reason you couldn't, then it becomes a different matter.

You don't have 3.43 gears. There's no such thing. Gears are a ratio of whole numbers, specifically, the number of teeth on the ring gear, divided by the number of teeth on the pinion. Can't have partial teeth. (at least not in a rear that works) The #s of pinion teeth are always somewhere around 10 or 11 up to as many as 15; ring teeth are always somewhere close to 40. At least one of those numbers is always prime (not divisible by any smaller numbers). What you probably have is 3.42, which is 41 on the ring and 12 on the pinion, that being common in trucks originally built in work truck configurations. It's a TERRIBLE gear for a truck, as you point out; even the "optional" 3.73 (41 & 11) is kinda .. inadequate ... for being "peppy", especially with larger OD tires on it. So yeah, no matter what you do about heads, that's one of the first ways to improve how the truck "feels".

Next best improvement you can make is a converter. It's ASTOUNDING how much difference a good converter makes, even with a stock cam. Putting in even more cam just makes the problem worse. Your truck isn't ready for another cam yet. It's not even ready for the one you already have.

That's what I'd spend my money FIRST on if it was mine, even before messing with heads or cam.

I doubt you'll be able to tell any difference at all from changing the intake & TB. That would largely be a waste. The way modding a vehicle works, to get best results, is to identify THE ONE thing that is MOST keeping the vehicle slow NOW, aka The Bottleneck; and attacking THAT ONE thing. More often than not, The Bottleneck will be something not fancy or glamorous, or even visible; like gears and converter. It's RARELY the big shiny obvious things sitting right up on top where you can see them, like intakes and TBs. It's not like you have an infinite menu where this "adds" 10 HP, that "adds" 25 HP, this other "adds" 15 HP" and so on; and you just pick and choose which ones you want to "throw" on it. That's import fantasy land. The only way that approach makes a vehicle "faster" is by weight reduction, centered on the driver's wallet. In your case, the intake and TB AREN'T The Bottleneck; not yet at least.

You don't mention a tune. What have you done about that?

^^^ This ^^^

Answering that question HONESTLY (work/towing, daily street driver, weekend toy, wife's "fun" second vehicle, frequent or exclusive visits to the strip, etc.) will help direct you further.

 

Yes I do have a converter, a 3200 stall by circle D
The truck is gonna be a weekend/street truck

 

Sorry I could’ve added more information I do have a tune by a reputable tuner in my area using HPTuners on 93

I do have a 3200 circle d stall

truck is a weekend/street truck

 

I could but for the 408 I’m going with rectangle port heads