[RetroLSX]

Motor options

I have run $300 5.3L LM7(cast iron early 5.3L)from 2005 Silverado with 33K from ebay put a used Z06 cam and $180 ebay headers and got 326RWHP and 323RW Torque with 87 oct at 26 MPG and these 5.3L are everywhere and cheap. The truck motors are filling up salvage yards because they last well over 200K miles so there is not enough demand for replacement motors in stock applications. This means these are very reasonably priced buys for great power and fuel mileage. Car Craft recently did a built with a low compression LQ4 with GM L92 heads and got over 500HP. Several 5.3L with under 10K miles with motor and transhave sold for around $1000-$1800 and the 07+ are all aluminum with pre production Z06 heads and a higher compression ratio that still go under $2K with a 4L65 trans!. It’s getting to the point that a LS swap is close to the cost of buying a GEN I 383 crate motor..






Bolt Pattern
All the new Gen III and Gen IV LS series engines feature a new bolt pattern on the block for the motor mounts so none of the tradition methods will work in adapting it to an older application. All engines from the 4.8L to the Ls9 feature this same bolt pattern.

Electronics

There are a lot of options to go on this route from rewiring the stock harness yourself or having a companies such as.
Speartech.com
CurrentPerformance.com
Wait4meperformance.com

GM also sells new plug and play wiring kits that include the drive by wire pedal for all 03+ Gen IV motors. Along with GM electronic kits to run the coil packs with a carb or the Electronic transmissions without the ECU. Just know that to control a electron trans a computer box is needed for the swap.
Fuel Systems

More choices here on this part of the install as well from buying a new tank from a company like Ricks hot rod shop, to modifying your stock tank with a modern fuel pump. LS1tech.com has a lot of good write ups and guides for this portion of the install for addition help as well. Or run a carb on your engine with the stock tank and a LS engine running in a weekend with the least amount of work.
Rock valley and ricks hotrod offer stainless EFI tanks but cost a decent amount close to 1K!

Some OEM looking replacements from Spectrat are 599 plus shipping that are sumped and baffled with a high volume GM EFI tank.
For the fuel filter regulator use
This is the part number from a corvette fuel filter

GM Part#10299146 (or Wix 33737)
(FPR), is from a 1999 C5 Corvette. Most time just ask for a fuel filter from NAPA or any parts dealer



The FBR will require fittings to adapt to traditional 3/8" lines and 5/8" return lines. One option is Russell performance

Fittings needed to adapt
(2) 3/8" fittings, part number RUS-639210 or RUS-640850
For the tank to regulator line and the fuel line connecting to the fuel rails
(1) 5/8" fitting part number RUS-640860
return to the fuel tank from the regulator

Front Accessories
GM is now offering the C5 and C6 accessories as complete kits for under $900 with A/C for a compact design with OEM quality at a reasonable price. Or without A/C for around $650
There are relocation kits for OEM truck,corvette, and camaro/firebird to top mount the A/C for a Sanden 508(Vintage Air Style compresor) for under $200
Or
Relocation kits for the PS and Alternator for under $300
Or just the ALT kit for $180


LS kits /Headers
A lot of options out there from Kooks, Hooker,edelbrock and countless others.

Oil Pans,

Each car need a special pan the LH8 or a this Custum pan i helped develped is best for these swaps. Or the Cady CTS-V, and autocraft pan work well if used with a A/C top mount kit.


This is only a very quick overview and a briefly touched on some of the big questions; I’m a big GM guy so I recommend keeping these conversions as much GM as possible. This will keep maintenances parts available at any local parts store and readily availably for a very long time. Ask me any questions you have about these conversions and I’ll be happy to help or at least guide you in the right direction of someone who can.

Shawn

[helimike77]

I have been thinking about doing this swap in my 65. Is it possible to run a non computer controlled 700r4 with these engines?

[RetroLSX]

Yes, all you need is the harness to run the motor and a spacer kit from GM with some longer bolts for the flywheel. Also TCI sells a flywheel already made for this swap. These motors can be ran with any GM trans and feature a bolt pattern very close to a SBC. Only one bolt will not line up.

[BillsCamino]

Do you take trade-ins of almost new hyd roller big blocks?

[Notalent]

Im just finishing my 496 build and thinking of selling it now. we are starting an LS program and you cant beat the cost/HP and weight savings.

[mjdwyer23]

If my garage was bigger, I would pull my 427 today.

[RYU]

To OP, Thanks for posting this. You've covered most of the key items. You'll probably get more questions on the motor mount adapter plates. I also don't like the LH8 oil pan since it hangs 1/2-1" below the crossmember. That custom pan you have looks interesting. Please PM me the price for that also the oil capacity?

Originally Posted by helimike77

I have been thinking about doing this swap in my 65. Is it possible to run a non computer controlled 700r4 with these engines?

Mike - check with Pist0lpete on here. I believe he's still running the 700r4 with his LS1. You'll need to figure out the kickdown cable mounting.

[73z-6sp]

I want an LS motor!! Oh...How nice it would be to have some money!

[RetroLSX]

As for the bigblock I know a couple people on here or at least ebay would be willing to take them off your hands! Don’t forget the gas mileage and dependability on top of the power to weight. These are under 450 pounds fully dressed.

The new pan is 5.5 deep 5 quart capacity and retail for 399 plus shipping.
Don’t forget about a budget 5.3L and 4L60! These in the car running will only set you back 2500-4000 with 400Hp and 20+ MPG!
The best way to build the tech in my mind is to ask questions and ill help in any way I can.

[BillsCamino]

PM me your shop's address and I'll drive over some day with my '67 and we can talk.

[mjdwyer23]

I'd be cruising there too!

[BowtieAaron]

great write up.

how far below does your custom pan hang below the x-member?

when i do the swap, i need a pan that does not hang any lower than the factory x-member, and the motor is somewhat stock location. my car is lowered 3" and the front x-member is 3.25" off the ground.

aaron

[helimike77]

Originally Posted by RYU

Mike - check with Pist0lpete on here. I believe he's still running the 700r4 with his LS1. You'll need to figure out the kickdown cable mounting.

Thanks for the recommendation. Ill keep that in mind if/when I do it.

[RYU]

Originally Posted by BowtieAaron

great write up.

how far below does your custom pan hang below the x-member?

when i do the swap, i need a pan that does not hang any lower than the factory x-member, and the motor is somewhat stock location. my car is lowered 3" and the front x-member is 3.25" off the ground.

aaron

I'm using a factory (unmodified) F-body pan. It was a super duper tight fit but it fit. So far the S&P modified F-body pan is good but it's only about 4 qtrs or so in oil capacity. They charge $285ish for them to modify your pan. The one proposed on here sounds like a better deal since it might be for a whole new pan. I just don't know how far it will hang below. The f-body doesn't hang below at all on my 66.

[BowtieAaron]

regan, thanks

aaron