I just picked up a 5.3L engine today and am thinking of dropping it in the Vette. I'm thinking about slapping on my brothers LS1 cylinder heads and his cam for right now, maybe later on in the future I'll add twin turbos. People out there with LS engines on their C3's be ready for questions.

 

Buy a copy of this book:

http://www.amazon.com/Swap-Engines-A...1275034&sr=8-1

and read the LS-swap thread. I'd be suprised if you have a lot of questions after doing both of those things. Also look on ls1tech.com. There is a ton of info on swapping LS engines there.



Rick B.

 

I'm going to make sure I go out and get it tomorrow. I'm also already looking through the ls1tech forum for info. Before I do this swap I'm going to fix a couple of other things on the vette. I can't wait to get this thing started.

 

I'll start off with my first question here: what mount plates are you guys using on your LSX swaps?

 

ttt

 

Give Trey at Speedhound a call and he can hook you up with most of what you need for mounts and other goodies. There are other vendors here as well. Trey has helped many out.

http://www.speedhound.com/

As far as the LS1 heads and cam, I might suggest saving some pennies and buying a decent head and cam kit as the LS1 set will provide little bang for the buck, even if free. If you are going to tear it apart, you may want to make it worthwhile. My .02.

Good luck with the project.

 

Actually, I'm thinking about using the LS1 heads and cam from my brothers '01 Camaro since he upgraded to the MS4 cam and PRC heads, so the heads and cam would be free. I'll make sure I make that call. By the way, your '81 Vette was a major inspiration.

 

That's kind thanks.

With regard to the heads/cam though I would suggest that you do a couple things. First off compare the flow of the LS1 heads to the stock 5.3 heads as well as the chamber cc to approximate what the compression ration will be (and I'm not even sure if the bore size works with the 5.3 but lets assume it does). I would then also compare the cam specs (duration/lift/LSA) to the stock.

I may get this wrong but if my memory is correct the 5.3's have a 3.78" bore whereby the LS1's have a 3.90" bore.

I am not sure, even if free, that you will find that the potential for increase will be worth tearing the motor down unless the 5.3 has a lot of miles on the drivetrain and you want to freshen it up.

Actually after writing above I went out and did a quick search. If the info I got is correct the LS1 heads have a larger chamber (66.67cc vs. 61.15cc) and at .500 lift the flow difference is negligible. You would probably loose some compression and some power. You might pick up a little something with the cam but I would spend about $500 and buy a good cam for the 5.3 with springs and hardened push rods and put the cam, springs and push rods in your 5.3 and keep your heads. You would save on heads gaskets and head bolts (couple bucks) so the net cost would only be about $300-$350 and IMHO you would probably make more power.

But, I would see what others think. I'm sure opinions will vary. Either way it will be fun when done!!! Enjoy.

Cam Specs:

5.3 LM7
190/191 int/exh @ 0.05" duration
0.466" / 0.457" int/exh lift
114 LSA

1998 - 2000 Fbody
202/210 int/exh @ 0.05" duration
0.496" / 0.496" int/exh lift
116 LSA

Head Specs:

Stock 5.3 Heads
Chamber 61.15 cc 0.100 0.200 0.300 0.400 0.500 0.550 0.600
Intake 200 cc 63 128 179 210 218 221 226
Exhaust 70 cc 54 93 121 145 163 168 174
Valve Diameter Intake 1.89"
Valve Diameter Exhaust 1.55"
Part Number 12559852
12561706

Stock LS1 Heads
Chamber 66.67 cc 0.100 0.200 0.300 0.400 0.500 0.550 0.600
Intake 200 cc 67 122 178 215 219 223 227
Exhaust 70 cc 52 97 133 156 170 176 180
Valve Diameter Intake 2.00"
Valve Diameter Exhaust 1.55"
Part Number 12559853 (1997-98)
12559853 (1999-00)
12564241 (2001-03)

 

What about if I swap valve springs and just drop the LS1 cam, do you think this is a good idea? I also just picked up a LS1 intake for it.

 

The 5.3 heads flow pretty good!A cam swap will really wake it up!
(another twin turbo C-3,,,COOL!)

 

So will the LS1 heads lower the compression on the LM7 engine?

 

Yes it will drop ... in this case about 5.5cc chamber increase results in about 0.5 comp drop ... IF, IF it were 9.5:1 w/ LM7 heads ... it'd drop to about 8.94:1 w/ LS1 heads ... not alot.

However, note LS1 has much larger intake valve ... that often results in wider valve spacing. It may, MAY be the LS1 valve spacing is too wide for small 5.3L bore ... upon opening, LS1 valve MAY MAY hit edge of small bore/block. LS1 heads may or may not fit, I dunno.

Thinking of rodding a 5.3L LM7? ... carcraft saw nearly 100hp increase in LM7 with CARB, stock heads but added just springs & cam. If that's to be believed, that's one heckuva bump!
http://www.carcraft.com/techarticles..._manifold.html

http://www.carcraft.com/techarticles...flow_test.html

 

Jordon, I think the concurrence here is that with just a cam and proper tuning that little puppy will rock. Headbolts, gaskets and the effort to swap the heads would cost you money to only lose power. Put it into a decent cam, intake, exhaust, and tuning and you will be well on your way.

Joe..

 

OK, I'm going to keep the LM7 heads and look for a good cam. Maybe later down the road I'll upgrade the heads and other parts. For now I'm just going to add the LS1 intake and drop it in. I think I'm going to drop in the Camaro since it's my daily driver, this way I'll save way more gas. I figured the vette only has 71,XXX miles and it's only going to be a weekend car, plus I want an LS2 for the vette.

 

To change the cam without removing the heads a little trick is to:

- get two 5/16" wooden dowels
- Remove balancer, timer cover, cam sprocket and let chain drop (Good time to replace chain and/or oil pump depending on mileage. If you replace the chain and not the oil pump, definately replace the O-Ring in the pick-up tube that goes in the bottom of the oil pump
- Pull the valve covers and loosen the rocker arms all the way
- While rotating the camshaft by hand, slide the 5/16" wooden dowels into the holes on each side of the cam. You may have to push a little to get to go past all the lifters. This will hold the lifters up so you can pull the camshft out without dropping the lifters in. Lifters are NOT accessible with the heads on. You can pull them up with a pen magnet as well as you go back into the motor with the 5/16" dowel but the dowel will hold them up while you work on it.
- Lube the daylights out of it and rotate and slide the new cam back in.
- pull the dowels out slowly
- reinstall everything.
- Depending on the cam, you will probably want to swap springs. Compressed air works wonders here or shove some rope info the cylinder to keep the valves from compressing while you use a spring compressor on them from above.

Cheers....

 

Will do. Thank you

 

In past couple of months either Super Chevy or Chevrolet High Performance did a complete article on the various Lx block & head combinations. They did include the 5.3, so you can go by the library & check out that issue.

 

I'm going to search through it right now.

 

? you're gonna swap both cam & springs right?

here's a cam swap method from sealed crate motor race cheats:

with motor out of car & on stand

roll motor-block over upside down

loosen rockers (Not remove) ... lifters will slide away from cam

R&I cam

roll motor-block over right side up

R&I springs

 

I like that!!!

Sometimes the obvious evades us.... Or at least me...

Just have a pan under the motor or hope it is thoroughly drained of ALL fluids when you do it.