Dburch89

Ok new too the site the only ls I have currently is the 4.8 in my 04 silverado and I love it. Now on to my question. First off my toy is a 41 chevy pickup that was subframed many years ago with a salvaged 79 ws6 trans am. It has every drive train component that would fit motor trans posi rear 4 wheel disk and the infamous 403 olds. While this one was well built and is the reason it was salvaged for the truck, it is loosing oil pressure and my heart transplant will be an ls. I plan to go carbed and plan on an salvage lq4. Can this motor be built to have similar low end torque output compared to the 403 ? Cause it pulls hard even with 2.73 gears. What cam would be a good choice ?

Dburch89

I know these engines are different animals and it won't be exactly the same I just wondered if I could still have some off idle tire burning torque. My 4.8 doesn't wake up till about 4 grand

2000ultraZ1911

That lq4 will beat a 403 every which way but loose....just do your research to see what combo you want ppl have tryd just about everything ls style motors.

2000ultraZ1911

Ur 4.8 is probly drive by wire which gives a really dissconneted feel which doesn't help plus a stock cam. But with ls style motors you get the down low with out giving up top end

Dburch89

Ya my 4.8 dbw and I know the torque management has a lot to do with it also, I've never driven an ls without it so I don't know how they feel. And yes I've researched cam choices and combos but it seems like all of them recommend running at least a 3 grand stall. I wanna drive it a lot and a 3 grand stall is a pain , I wouldn't mind maybe a 2000 rpm stall. Ill be running a 350 turbo for now and the 2.73 gears until i get overdrive .I want the power band to start early even if it doesn't pull to 7000

Dburch89

I know the cams with high lift and lower duration make the most torque but I would like to keep it around .550 on lift to make my valve springs last closest thing I've seen lookin at dyno charts was a reverse split any experience with those?

65impalass

What trans are you running? The 6l90 has a 4:07:1 1st gear that would pull hard with your rear gear.

ijimmy

If you pull a plug wire off the lq4 it should be close

Dburch89

Plan on running a 350 turbo for now and I'm not against changing the rear when I do get an overdrive but for now it makes helps me cruise at a reasonable rpm with a 3 speed

Dburch89

So I found a complete running 5.3 for 300 dollars is it worth getting so I can get my engine bay set up for an ls, motor mounts ,get headers to fit ,wiring etc and run it for awhile so I can build the 6.0 like i want l92 heads with a lightweight valvetrain and stroke it to a 403 lol. From what I read a .005 hone and a 4 inch stroke comes out roughly to a 403 on a 6 liter

i r teh noobz

iTrader: (4)

300 is a good price if its complete. Perhaps you should consider a mild cam for the 5.3? Hop it up just a little and build a killer engine on the side.

My 5.3 will shred tires at any RPM, even with a cam that doesn't wake up till 3000 RPM. I do have a manual trans and 3.70 gears though.

71403

Unless you have a dual pattern TH350 that BOP pattern trans isn't going to mate up with the LS motor. Update the trans now and get it over with you won't regret it. E-shift trans and OD will make more of a driveability difference than going from a 403 to a LS motor.

I went mild 403 -> stock 6.0. More power, better mileage, front end came up an inch. Biggest regret was keeping the 4L80e and not going to a 6Lxx trans.

403 was a great motor *for it's day*

Dburch89

What cam are you running I've looked but there are so many choices, the one I really think I would like for the lower power band is the smallest comp thumpr it says stock converter is ok

Dburch89

I know I have the big olds Bolt pattern tranny, I was thinking I could run the adapter plate that makes it a sbc pattern they have them in the summit magazine it is a well built trans and since I want to go carbed I was planning on changing to a 700r4 a 4l60 or 80e controller is expensive, of course so is everything else but the cheapest one I have seen is like $1500

Dburch89

Ok I found my mistake on the transmission controller price,the one I was looking at came with a paddle shifter tcu from tci or b&m runs around 600 dollars so what would be the benefits of the electronic controlled tranny vs the 700r4 both of them being performance built

71403

No AFT bath to change shift feel. No going under car to change WOT shift points. No TV cable, no messing with TV cable geometry to match the power rise of the engine. Shifts when you want, how you want, every time.

$600 for trans controller, $600? for MSD box and carb intake (no carb), you're getting to the price of a complete 5.3 cutout with trans, harness, PCM in some areas.

i r teh noobz

iTrader: (4)

I'm running a 224/228 112 from Texas Speed. I'd recommend a "smaller" cam, especially with 2xx gears and an automatic. Just making the point that a 5.3 can be plenty of fun.

Maybe contact PatG? He gets alot of referrals around here. A smaller custom cam and some LS6 valve springs would be worth a look.

Adam123

iTrader: (1)

You could keep the engine EFI and let the ecm control your new transmission.