Neptune75

Im in the research stage. so for the last few days i have narrowed it down to ls3 or ls7. i guess what prompted the swap is my classic 1 ton truck with a 454 got a little weak. so i was thinking build a 496 for the truck... but then it dawned on me. take the 496 out of the vette problem solved!
which leaves an open drawing board for a ls swap. i really like the dry sump and titanium goodies in the ls7. on the other hand i like the lower compression and price of the ls3. i want to stay with automatic trans i guess i need some input on what you guys would do. to justifie my insanity?

DRIVESHAFT

What I would do is leave the 496 in the Vette.
If your craving an LS swap, put it in the truck.

Vette5.5

Your large, heavy truck's a good place for the 496, as ton's of torque, but your Vette's a good place for it too. LS7's are one heck of a motor, as have one in my C6. Problem is, new in crate are $15K, and don't think you'll find many on the used market. GM's cost on the Ti rods, is almost $2K alone. LS3's are really 9/10's, and surely you can find a used one for far less. Big advantage of LS's are, very light at 440 lbs, head flows over 300 cfm, and mine gets 25-26 mpg highway all day long with T-56 6 speed. Josh at Custom Image Corvettes in SD, can help you out with anything LS conversion, so maybe give him a call. Also, World products makes a cross breed block, thats all original SB down low, and LS on top, for the better breathing, modern head/injection set up. Drops right in.

Garys 68

No offence but I dont think many C3s can pull enough Gs to need a dry sump.
A used LS2/3 with a supercharger will have more HP and torque for less money. In addition there are a kot of aftermarket motors available.

Vette5.5

I agree with "Gary" on the dry sump, as road track my C6 LS7 car several times a year, with most of the group better drivers than me in conventional wet sumps. Never seen anyone with oiling problems yet. Super chargers certainly add power, but add their own share of problems too. Mostly with a proper air to water intercooler set up, lot's of extra weight hanging over the front axle, just where you're not wanting it.

ipmtim

Neptune,
I have a '06 Z as well as a '71 and hang out in the C6Z forum.
Before you spend a whole bunch of money on and LS7 go there and search for valve guide issues.......its not pretty!
62K on my clock and the heads have to come off for a rebuild before the ticking time bomb drops a valve and vents my block.
Tim

Corey_68

Lsx 454

tekvette

LS3 would be the way to go if you weren't planning on big cubes. Wayyy cheaper.

holley505

I got a LS3 stroker from Texas Speed - short block. 418ci (almost 427 inches) but WAY CHEAPER...

I run AFR heads (haters they are catherdel port mongoose 205) I had them and they are in good shape why run something else???

TSP cam - 246/256 608/610 112lsa - nice idle with a nasty lope

I have a TH400 with hughes 3500 stall. (i broke my built TH350)

My car go HIGH 10s with a 3.36 gear on 275/60R15 Mickey drag radials. I run pump gas and can drive anywhere... including the TRACK. 6.9-6.8 at 100mph on the 1/8th...

OH YEAH... its got a VIC JR with a HOLLEY DP CARB!!!

l88rocket

lsx 454. if your going Ls might as well go big as you can

Neptune75

I lurked in your posts for a long time and followed it with great inetrest. im blown away with the time's... and power your getting out of that engine. what is your mpg through that carb ad th400?

if im reading this right these engines bolt to the old turbo 400 trannys?and if so, do you like the tranny ls combo?

Neptune75

Thanks for the input, i think were on the same page... i would like to put 9k miles on the car in the very short michigan summer. insted of 900 miles and sunday car shows.... i understand im loosing a bit of torqe and hp but..... but MPG and a driveability would be more ideal.. and i would like to take on the challenge of the swap in my corvette. it has always been a never ending "model car". and hobby of mine.

Neptune75

i will.. thanks for the info. any "must know probs with the ls3???

Neptune75

Crazy.. i just watched a show on corvettes on the history channel the showed the building of the frames and about mid show they did a part on the had built ls7's in wixom michigan. and my High school girlfriends dad, was the the "hand Builder" of the engines. and he was the focus of the show for about 15 mins... His name is greg jones... every one here in southeast michigan works for one of the big 3.. but it was very cool to see that. is this a "sign" .......(maybe a higher power is pushing me to the ls7)..

Neptune75

good point..

mirage2991

LSX 454 or have an LS built...some LS7 have drope valves, though no one knows why...but I wouldn't buy one because of the price tag...when you can get an LSX454 for 5k less with 115 more hp...

by the way, the LS7 dry sump is really not a "dry sump" like on a race car...it still only use one stationary pick up in a shallow pan.
I real dry sump has more than one pick up point, moving pick up and more...

ajrothm

Why not just build a 496" for the truck and leave the Vette alone? The Vette is done and has a good combo, why mess with it and likely make less power?

ajrothm

If you do decide to go LSx, I would also go LS3 based 418"....best bang for he buck.. Or if youre willing to spend the money, stroke it for 429". With the right parts you can make 650 crank HP or so..... Or about the same as your 496..

Spacecoast

I can't speak to mpg, but can attest this car is a BEAST. I believe the th400 fit in with no problems, but I am sure Sean will chime in.

qwank

LS7 in the truck!!!