C4 Corvette LS1 swap...

[kpforce1]

****PART I*****

***** most of the info for the 700R/4L60E in this swap is courtesy of CHarris85Vette on corvetteforum.com********

Ok, I figured that a separate thread for this would be nice to have so I will post up as much as I can as often as I can. To start off, my car is an 1984 Corvette. It was the crossfire with a 700R4 and a Dana 36 rear end. I wanted something pretty unique and able to kill pretty much anything on the street without killing street manners so I decided to put an LS1 in it (the streetablility and potential of the LSx platform is quite astounding).

*TOP 10 LIST of things to seriously consider before doing this swap*

1.) If you don't have a budget of at least $7,000 (preferably a budget of $10,000 for a well done swap)... don't even attempt to have a budget less than that uless you have the engine or engine tranny pullout already. Your overhead cost will be less than mine because I spent a pretty penny on trial and error.... but you don't have to.

2.) You WILL run into a few snags as with any "custom" project (except you will have a guide to help you unlike I did) so ask yourself if you are willing to tackle what ever "snags" arise... some small and some potentially big.

3.) Do you want a 6 speed or an auto tranny (if auto I would highly suggest the 4L60E to get rid of the TV cable.... at a minimum a 700R4 upgraded to 4L60E standards/internals) *note* The only OEM type 6 speed that has currently been mated to the LS1 is the T-56 type transmissions. I know of someone doing an LS1 ZF 6 speed swap and he said some sort of spacer has to be placed between the bellhousing and the engine but can work... just isn't tested yet. I think that the TKO type trannys will work as well but you will have more clutch solution problems i think.

4.) I would HIGHLY suggest a Dana 44 rear with the LSx type motor no matter what tranny you are using because BIG power can be made with hardly anything on LSx motors (if you do this swap, you wanted more power anyway... probably 370+ rwhp so a D44 is cheap insurance... well, not cheap but you get my point).

5.) Do you want to retain the A/C system? Stock heater functions?

6.) Are you going to retain as much of your OEM wiring harness as possible and splice/modify it for the swap (particularly the fuse box and all switches) or would you rather gut most of the stock harness and use something like Painless or "Its a Snap!" like I did?

7.) Do you plan on keeping your current dash and gauge cluster setup or would you like to have a custom type gauge setup (seems to be the popular/easiest solution), custom dash, or both?

8.) Would you want the throttle by wire function on your car (approx. $250-350 more) or stick with cable type throttle?

9.) How much frame notching and fabrication work can and are you willing to do (this is importaint because different motor mount adaptor plates place the engine lower, higher, further forward or backwards.... your tranny type, if you want to use headers, shifter position, and less frame fabbing could help determine what you need)?

10.) Would your use an OEM LSx harness and rewire it to fit your application or would you be willing to pay a decent chunk of $$$ for a custom made one for your application from a place like Speartech like I did? Another consideration would be for the type of computer you are going to use.... i.e. Corvette (LS1 or LS2 type?), Camaro, a different OEM type computer, or a standalone system (such as FAST, Painless true fit with computer, Big STUFF, etc. etc.)....

Oh, another think to ask yourself is will you have to have emissions? If so you will need to look up regs on engine swapping.... but I think that swapping a "newer" type engine into an older car isn't to much of an issue.

These are just the top 10 things I could think of that a person should consider before diving head first into the LS1 swap like i did... have a realistic goal for what you want so you can figure out what you need and be true when figuring out what you want when considering these 10 items. It will help you in the long run.

I am in the process of writing up steps to do the actual swap (LSx with a T56 in my case) and I will get others who have done LSx swaps to post other pertinent information. Be patient, because it may take me a little while. Pictures and install info/tips will be up as soon as I can get them here.

And YES my car is driveable as of Sep. 11 2006 It is a cammed LS1 with full exhaust and modified C5 vette 1 7/8" headers with a modified B&B 3" exhaust with X-pipe.... I could burn the tires off at 55+mph and I'm only using milled Stock LS1 heads.... it is stupid fast. :partyon: but thats exactly what I wanted.

[Matthew]

cool! C4s weight about 2800 correct?

[93Polo]

Most of the non Zr1s were 3,100 to 3,3000 lbs

KP you may have answered this on CF but what mounts are you using and did you modify the front cross member? Also what oil pan are you using, C5?

Thanks,

[kpforce1]

******************PART II*****************

Ok, once you have considered the things I mentioned above you should have a general idea for what you want in your project. I'll begin discussing a few modifications you will have to make depending on the type of motor mount plates you use. There are two different motor mount adaptors commonly used on this swap (not that the swap is all that common... but I hope that changes ).

If using motor mounts like the one below the modifications required are discussed below the picture:



1.) If you want to use the C5 corvette oil pan you have to notch the frame for the pan to clear. Another option is to use the Camaro oil pan so you don't have to notch the frame.

2.) If you are going to use stock Z06 manifolds you will have to notch the frame for them to clear as well. I think stock LS1 corvette manifolds may just clear but probably not. You can use MAC mid length camaro headers to avoid this as well. The third option is to fabricate your own headers or have someone fabricate them for you ($$$$).

3.) If you are using the 700R4/4L60E you will need a D36 C-Beam and move the front and rear holes (1/8" towards the tranny in the front and 1/8" towards the D44 in the back). I think you can use your current torque converter with the use of some longer torque converter bolts and a spacer of some sort (don't remember). You could also switch to an LS1 type flexplate and converter.

4.) If you are using the T-56 it should be the LS1 F-Body style with the push type hydraulic slave cyl. You will have to have a clutch hose fabricated out of a stock C4 hydraulic hose and an F-Body hose (if you want the quick disconnect function). The C4 Clutch master will work fine. You will also have to get an adaptor bracket so the T-56 will mate up to the C-beam ($200). I think that the D44 C-beam will work but I can't say for sure.... the T-56 is longer than the 700R/4L60E at the C-beam mounting location on the adaptor bracket and thats why I think the D44 C-beam will work. I know the D36 C-beam will work you may have to cut a little off of the end to clear the T-56. Both the D44 and D36 C-beams will have to be modified to fit the T-56 adaptor bracket (hole elongation and a 1/4" notch on the top to clear the shifter housing). I'll get more into detail on the T-56 portion later.

5.) The stock C5 thermostat housing will barely clear the A-Arm mount but will work. You can always get a straight waterneck from street and performance for $75 and I know the part number of a radiator hose that fits perfect on it.

6.) The engine cradle mount will have to be elongated like so on the passenger and drivers side (red denotes area to be elongated in picture below).


7.) The C5 powersteering hose will have to be bent quite a bit to fit the C4 rack



If using motor mounts like the one I made below (they are also available from street and performance) the modifications required are below the picture:



************************NOTE********************** ****
Using this type of mount will place the engine 1/2" to 3/4" of an inch lower in the engine cradle changing your center of gravity (for the better) and will shift the engine approx. 1-1 1/4" further back than the stock CFI/TPI/LTx engine. You will loose a little ground clearance due to the engine sitting lower.
************************************************** *****

1.) You can use the C5 corvette oil pan without notching the frame. The clearence is tight but it will clear fine. You can also use the F-body pan if you so wish (but why ).

2.) The C4 frame engine cradle mounts HAVE to be notched straight out OR down towards the wheels at no more than a 45 degree angle for a 700R/4L60E. If using the T-56 the cradle mounts HAVE to be elongated down towards the wheels at a 30-45 degree angle or the T-56 will hit and rub the transmission tunnel (red indicates area to be elongated in the picture below).



3.) There is a place on the firewall that needs to be "shaved" if you would like to remove the exhaust manifolds/headers after the engine is in. See picture below for the rough cut I made (i discovered I couldn't put the last manifold bolt in and cut it). There is a top down picture to show the area that needs to be modified below as well.




4.) The stock thermostat housing WILL NOT WORK with these type of engine mounts. You have to get a straight neck housing from street and performance ($75) or Katech ($110). I have the part number for a direct fit radiator hose using the straight neck housing as well.

5.) The C5 power steering hose will not have to be bent at all to fit with these mounts.


*******************This is a common modification for both type motor mount adaptors************
The inner side of the heater core box will have to be removed if you want to remove the heads from the block while in the car. You could cut and modify it to clear or buy the 2 piece ZR-1 heater box cover (part #'s comming soon) as well. The LS1 coil packs will hit the stock heater core cover as well requiring the passenger side coil bracket to be modified or the heater cover to be modified.

************************************************** ***********



WELL FOLKS.... THIS IS ALL I HAVE TIME TO DO TONIGHT..... I'LL DO MORE AS SOON AS I CAN..... :partyon: STAY TUNED!!

PICTURES:

[kpforce1]

Originally Posted by 93Polo

Most of the non Zr1s were 3,100 to 3,3000 lbs

KP you may have answered this on CF but what mounts are you using and did you modify the front cross member? Also what oil pan are you using, C5?

Thanks,

I'm using custom mounts that I made to shift the engine/trans back an extra inch. I did not have to modify the front crossmember but because the mounts shift the engine back the extra inch the engine also has to be dropped 1/2 an inch so the tranny clears the transmission tunnel. It would be a good idea to flatten the raise in the front crossmember before putting the LS1 in so you have more than a 1/16 inch clearance from the harmonic balancer to the crossmember.

I made my engine mounts by using a set from ebay (the street and performance type) and using a 12x4.25x1/4 inch pieces of steel from the Home Depot. You just place the Ebay mounts on top of the steel plates, put in a vice, mark the LS1 mounting locations, and drill them. After that, use the LS1 hole locations and move the Gen I holes 1 inch further back.

I am also using the C5 vette oil pan.

[zigroid]

hmmm, this is tempting. I have an LS2 that needs a home and I have always liked C4 vettes.


how hard is it to work on? would a cam swap in car be possible?
how is interior space on a C4? I sat in one a long time ago but I was 14 at the time. Im a rather large guy at 6'2" 240 lbs. not fat, just large frame. I can't think of anyone local or nearby that I could see how well I fit.
what would be a good price to pay for an 80s vette?
I don't have alot of cash to work with but I already have an engine, transmission, and torque converter. Id imagine an 80s C4 would be cheaper.
are there any disadvantages to starting with an 80s C4 as opposed to a 90s C4? didnt the 90s C4s get ZR1 style quarters so they could run wider tires?
how weak are C4 rears?

[93Polo]

Originally Posted by zigroid

hmmm, this is tempting. I have an LS2 that needs a home and I have always liked C4 vettes.


how hard is it to work on? would a cam swap in car be possible?
how is interior space on a C4? I sat in one a long time ago but I was 14 at the time. Im a rather large guy at 6'2" 240 lbs. not fat, just large frame. I can't think of anyone local or nearby that I could see how well I fit.
what would be a good price to pay for an 80s vette?
I don't have alot of cash to work with but I already have an engine, transmission, and torque converter. Id imagine an 80s C4 would be cheaper.
are there any disadvantages to starting with an 80s C4 as opposed to a 90s C4? didnt the 90s C4s get ZR1 style quarters so they could run wider tires?
how weak are C4 rears?

6'2" 215lbs here and I have owned a C5 and a C4. The C4 IMO had more head room.

C4 prices depend on several things but 5g to 10g for a good car maybe less if it is not running.

In 90 the new dash appeared, 91 introduced the more rounded bumpers with Zr1 style tail lights. You can updated the bumpers and molding in the early C4s to the later C4s, hood, quarters, doors are the same for all year excluding Zr1s.

[kpforce1]

A cam swap is very doable with the engine in the car. The radiator just has to come out. Changing the spark plugs is actually very easy...

[Tuf-Titan]

Thinking of putting one in my 96?

[kpforce1]

Just an update for anyone who's following this.... I got the header fabricated as well as the 3" dual exhaust with X-pipe. Got her started up and took it far a test drive.... let me tell you... at 50 mph I could smash it and it would break the tires loose. lol 1st, 2nd, and 3rd will all spin at will and I'm sure I can bark 4th but I'm still breaking in the clutch and rear.

[Beaflag VonRathburg]

This is great. I've always loved the body style of the C4 Vettes and have always wanted to see one with a LSx.

Are the only long tube options to chop up and reweld a set of c5 headers or are there headers specifically for this type of swap?

Good job on the swap and keep us updated.

[kpforce1]

Ok, i just changed my first two posts to make this a sticky if people feel it should be.... Thanks Oh, i have the T56 out right now to rebuild it (got ripped off for a bum tranny).

Scott

[sway99bird]

Any more updates

[jfg455]

Subscribed. I like it. I had an 87 vert I thought of lsxing. Sold it instead. Nice work.

[the_merv]

Nice, I have a friend with an '84 that I have been nagging about going LS..

[jfg455]

any news fit to print?

[kpforce1]

Well, The poor car has been just sitting around waiting until this week. I just ordered some Katech rod bolts because I run it upstairs (6800rpm), Optima battery and relocation kit because I had to put the PCM where the stock battery location was, various C5 dash/console pieces, a push button start system from kptechnologies, and a c5 steering column because the stock c4 column would not work properly.

I'm starting the project again and I will hopefully have some more to add. On a side note, i did get the C5 dash fully mounted in the car (pics below)

[frankmarroquin]

If u dont mind me asking what powersteering pump are you running? i am currently in the middle of my conversion on my 84 Vette...

[1986irocz28]

subscribed