Taking the LS3 Plunge

[TnBlkC230WZ]

Getting my car ready for the RTMC event and figured I still have time for an LS3 swap. I've really leaning towards the erod engine package. Independent dynos put it at about 480 - 490 HP which is plenty for my needs. I'm still open to other ideas, but the idea of a green and quiet engine is very appealing. I have a few starter questions below.

1. Where is the best place to purchase the engine? The best place I've seen so far is the crate engine depot.

2. What are the best motor mounts? I need the bellhousing to be in the same place as the old 350. I'm tying to avoid purchasing another driveshaft and I have no room to move the transmission back.

3. Which fuel filter/regulator should I get. I've read the Corvette part is best, but is there a specific year/PN that is best or easiest. I'm running -6 fuel lines front to back with a Ricks tank in the car already.

4. What front end accessory kit fits under the hood of a 3rd gen Nova? I prefer to use something OEM but I also need to mount my AC compressor?

5. Lastly, the clutch; I don't know if I want to keep my SBC bell housing and mechanical clutch or make the jump to hydrolic. I'm happy with the mechanical. What is my best route for a hydrolic clutch using OEM parts. Also, Is the LS7 clutch the best way to go for 500 HP and will it fit inside a Gen 0 bell housing?

6. What is the best way to hook up the cooling system to my current radiator. It is aluminum, so I can change the openings if needed.

I'm sure I'll have other questions, but I need to get the big parts order and in my garage by next Friday.

[garys 68]

1. Shop around, SDparts, Crate engine depot, even local dealer. Dont forget to include tax and shipping. If you're getting the crate motor and harness, they're the same no matter where you get it.
2. Edelbrock makes plates that leave the trans in stock locastion.
3. 02 corvette filter/regulator
4. Check on LS1tech for Nova conversions for options. GM sells the corvette complete assembly, Kwik Performance has something similar and a high passenger side AC mount.
5. SBC 153 tooth bell housing wont work. A 168 #621 will. Keisler makes a heavier 621 version with the extra LS bolt hole. An LS flywheel/26 spline clutch will bolt up with LS7 pilot bearing and longer throwout bearing. A sachs 1050 flywheel/11" 1968 BBC 10 spline clutch, 1 1/8" throwout bearing will also work. You can keep the Z bar or Keisler sells hydraulic bearing packages.
6. I'm using the stock rad with modified truck upper hose.

[TnBlkC230WZ]

5. It may make sense to make the hydrolic switch. I should be able to find a used LS bell housing cheap enough.


1. Shop around, SDparts, Crate engine depot, even local dealer. Dont forget to include tax and shipping. If you're getting the crate motor and harness, they're the same no matter where you get it.
2. Edelbrock makes plates that leave the trans in stock locastion.
3. 02 corvette filter/regulator
4. Check on LS1tech for Nova conversions for options. GM sells the corvette complete assembly, Kwik Performance has something similar and a high passenger side AC mount.
5. SBC 153 tooth bell housing wont work. A 168 #621 will. Keisler makes a heavier 621 version with the extra LS bolt hole. An LS flywheel/26 spline clutch will bolt up with LS7 pilot bearing and longer throwout bearing. A sachs 1050 flywheel/11" 1968 BBC 10 spline clutch, 1 1/8" throwout bearing will also work. You can keep the Z bar or Keisler sells hydraulic bearing packages.
6. I'm using the stock rad with modified truck upper hose.

[dhutton]

I thought it was Hooker plates that left it in the stock position and that is why they place it so close to the firewall. Not sure that Edelbrock plates do that, I think they place it further forward.

[garys 68]

Edelbrock now makes 5 different sets of plates, one of them puts the engine in stock location.

TnBlc,
What trans are you using? The hydrulic throwout bearing kits are $500-600, so I kept the Z bar.

[neki67]

I thought it was Hooker plates that left it in the stock position and that is why they place it so close to the firewall.

You are correct, the Hooker plates don't change the position of the transmission. Edelbrock has the same kind of plate.

By using these plates and providing you use the same transmission and rear axle as before, there's also no need for a different (i.e. longer/shorter) driveshaft.

[dhutton]

[QUOTE=garys 68;772423]Edelbrock now makes 5 different sets of plates, one of them puts the engine in stock location.
QUOTE]

Do you have a link? I just went through all this and did not come across these in my search. Thanks.

[TnBlkC230WZ]

I'm running a T56 Magnum with Keisler's adapter plate.

[andrewb70]

I can vouch with 100% certainty that the Edelbrock mounts (their original mounts, I don't know about the various options available now) put the bellhousing in exactly the same location. This was critical when I did my LS swap because I retained my transmission, shifter location, and driveshaft.

Andrew

[dhutton]

I can vouch with 100% certainty that the Edelbrock mounts (their original mounts, I don't know about the various options available now) put the bellhousing in exactly the same location. This was critical when I did my LS swap because I retained my transmission, shifter location, and driveshaft.

Andrew

I think we are mixing A body and F body mounts into this discussion. I was referring to the F body mounts but I think you are referring to their A body mounts. They have two different part numbers.

[andrewb70]

I think we are mixing A body and F body mounts into this discussion. I was referring to the F body mounts but I think you are referring to their A body mounts. They have two different part numbers.

The chassis is irrelevant for the sake of this discussion. Engine placemen is determined by the chassis frame stands, and in this case with the adaptor plates. The actual engine mounts are the same for a-bodies and f-bodies.

So if you remove an old sbc or bbc from a Camaro, retain the same frame stands and engine mounts, and use the Edelbrock adapter plates, the bellhousing of the LS engine will be in the same place.

Andrew

[garys 68]

Sorry, I was looking at Hookers, 12611HKR (Stock Location).
Edelbrock 6701 are advertised as stock location, but looking at them compared to Hookers, they may be 1/2 -1/4" forward.
I've got a set of Speedhounds, advertised as stock location, they look like edelbrocks. But on my 72 442, they look to be almost 1/2" forward.

[dhutton]

Edelbrock lists plates 6701 for A body and 6706 for F body on their website...

[TnBlkC230WZ]

I've got the engine, clutch and some other parts ordered. I'm working on the motor mounts. There are five styles of Hooker mounts and sure enough, they have a set that puts the bell housing in the stock location. I still need to get the Energy suspension mounts. Should I get the tall or the short ones?

Note: These mounting plates may allow me to use the oil pan that comes with the LS3 engine. They are about 1.25 inches farther back than most of the mounts that you see.

[garys 68]

Motor mounts will depend on your frame mounts.
See this link.
http://www.ls1tech.com/forums/conversions-hybrids/867789-motor-mounts-68-cutlass-gm-body.html

[TnBlkC230WZ]

Motor mounts will depend on your frame mounts.
See this link.
http://www.ls1tech.com/forums/conversions-hybrids/867789-motor-mounts-68-cutlass-gm-body.html

Very helpful, thanks!

[dhutton]

A great comparison of plates posted here by Mike Kelcy:

http://firstgens.com/forum/16/ls-conversion-motor-mount-brackets-317.html

[TnBlkC230WZ]

The Doug's plate looks like nice, but I can't find a part number on them. They are not in Doug's catalog.

I'm trying to determine if the Corvette oil pan that comes on the LS3 has any chance of fitting my 3rd gen oil pan even if I use the set-back mounts. The sump looks too long in the pictures. I was hoping it came with the F-Body oil pan, but it doesn't look like it. I may get the AutoKraft or Mast oil pan and not worry about it.

[TnBlkC230WZ]

What size is the throttle body on the LS3 Crate engine? I'm looking at the Spectra intake tubes but don't know what diameter to get.

What size oil pressure and water temp fittings do I need? My Autometer electronic temp and pressure gauges have 1/8 NPT fittings on the sensors. I've heard the LS engines have metric ports. Also, does anyone know the best place to put them?

[garys 68]

Temp adapter in rear of passenger side head.
http://www.speedwaymotors.com/LS1-Water-Temperature-Sender-Adapter,8195.html
Oil adapter in stock sender location. Or you can tap the fitting over the oil filter.
http://www.speedwaymotors.com/LS-Series-Oil-Pressure-Sender-Adapter,20928.html