YULOST

I really need some information on this motorswap, help is greatly appreciated, anyways right now I have an 85, with its L98 and 4 speed manual. I purchased a head cam LT1 with a T56 to go along with it, and would like to put it in my 85. I have the LT1 computer. Obviously I need a clutch and a LT1 wire harness. What else is needed, also advice and recommendations.

bogus

I will be blunt, these are the types of questions one asks BEFORE buying expensive components.

However, I am doing a simular conversion in my wifes 87 Vette. LT1/4L60E.

What is the LT1? Was it an automatic? A manual? Were they a pair? Details, please. For a stock-ish LT1, stick with a stock clutch. It will hold quite a bit.

You need to get the brackets for the T56 to fit into the C4. I don't remember who makes them, but do a forum search.

You will want to reuse the L98 motor mounts and fans. If you don't already have the heavy duty fans, get them. The PCM for the LT1 uses 2 fans.

What year is the LT1? The ECM?

The harness will need to be adapted to fit the dash/IP/DIC/etc of the 1985. You will need Helm Service Manuals for both the year of your car and the year of the engine!!!! If the engine came from a Camaro, get a Camaro book of that vintage. www.helminc.com. You will NOT complete this project without both guides.

coupeguy2001

If it were me, I would use everything I could off the L98, including the MAF, wiring harness, and computer, and change the ignition over to the smaller camaro L98 ignition distributor with divorced coil.
Have a machinist drill and locate the distributor hole, and fabricate the spacers for the distributor.
The engines are so close in design, I think that would be easy.

BrianCunningham

How's that going BTW?

bogus

about 85% done. The last task is to integrate the electrical with the car.

YULOST

Thanks for the help, I believe everything is out of a 94 Z28, The motor was last with an automatic trans, the trans i have now was not paired with the motor.

bogus

oh. I am not exactly sure what to suggest now. I am not sure how the Camaro LT1s are balanced....

If you put a misbalanced flywheel on the LT1, it won't spin up right. I just don't know what to suggest here... I wish I did...

Perhaps someone who knows more on this conversion/subject can chime in.

YULOST

I do need a wire harness though correct? or will the l98 harness work?

JLeatherman

www.prostreetcustoms.net

They sell the bracket for the T56 swap. Click on the C4 link on the left side. It does require some additional machining, though, and some modifications to the shifter cover.

500hp

You will need the flywheel and clutch assy for an LT1 F-body. The F-body flywheel is lighter, their T56s were mounted to a crossmember, and their steel driveshafts had their own dampers, so they had fewer balance issues/concerns. Try checking with McCleod for a hydraulic clutch actuator assy. (the ZF6 C4s and T56 F-bodys used the same PULL style pressure plate), or they may just have the separate parts needed for the C4's firewall mounted master cylinder and the T56's bell hsng. mounted slave cylinder (then just plumb the two together). It seems Keisler doesn't like to sell their swap specific specialty parts unless you are buying the whole freakin', overpriced kit w/tranny. However, you may be able to squeeze a little tech info out of them.

You should probably locate the accessory mounting bracket for an LT1 Corvette (good luck). The '94 alternator might work, but the power steering pump may need to be re-plumbed or the hoses re-routed. Check the part numbers to see if the F-body idler/tensioner cross-over to the '93L-'96 Corvette (if any of this stuff came with the engine).

The '85 exhaust should work okay, but you will need a 2nd oxygen sensor/bung installed. You will need fuel fitting adapters for the lines coming off of the fuel rails, and for the '85 chassis' fuel lines (pretty common in the aftermarket).

You will also want the ECM and wiring from a '94 or '95 F-body, preferrably a 6 speed car's (an automatic harness may require a few mods, the ECM can just be re-programmed).

Of course, there is also all the required mods for the tranny's tailshaft mounting. The T56 uses the smaller 27 spline slip yoke, so you may want to start with an automatic C4 driveshaft.

I'm sure I am still overlooking many other issues. A/C compressor and plumbing, Corvette LT1 damper and hub, T56 shifter location, etc.

bogus

Don't use the L98 exhaust!!! Get LT1 exhaust for a Corvette.

Then use the brackets from an LT1 Vette.

What I am not sure about is how you will mount the forward bracket... it's mounted to the gearbox. And you won't be using a C4 gearbox.

YULOST

nice, thanks for the info

YULOST

also I purchased some hooker super comp long tube headers for a 94 vette, (figured they bolt to the lt1 engine, and fits inside the corvettes engine bay) they should fit, right?

YULOST

well we started the project, everything has been ripped out, old motor, 4 speed, old engine harness (the easy parts out of the way!). Im still looking for a harness - Put the motor with the bellhousing in, the headers fit perfect, I did have to use the motor mounts off the l98, and the l98's starter worked. we still need to put the trans and driveshaft up, wire the car, modify the center counsel for the shifter

YULOST

trans is in, center counsel cut out for shifter - but the driveshaft would not go in, it seems to be a bit too long. I hear an automatic driveshaft would work. Is this true before I waste any more money?!?!!!

bogus

I don't know... bump.

BTW, do a search on this... I know it's been done.

JLeatherman

I think an auto driveshaft is too short. If it were me I'd have the driveshaft shortened by a machine shop so you know it's the right length.

cv67

They will tell you where to take measurments from so it fits correctly. Think it costs about $75 to have one cut and balanced.

LD85

T56 help here ask for Bob

http://www.weirhotrodproducts.com/id2.html

YULOST

I dont know which ******* I talked to, but he says that the driveshafts from the manual and automatic cars is the same lenght, is he full of ****, or could this be true