I have a 86 iroc 305 tpi automatic, I can get my hands on an lt1 with a 4l60e pretty cheap with everything. Im talking full motor wiring harness, computer. I was wondering what it would take to drop that eingine into my car. Do the motor mounts match up, would I have to run the exhaust different, etc.....

 

Motor mounts line up, so does exhaust. There have been plenty of extensive threads, do a search. Wiring and computer simply need to be swapped. If you run AC, the K Member needs notching. Custom fuel lines are needed. The TPI throttle cable is needed. There are a lot of little things. Also, search for a guy named "LT1Powered85Z"

Good luck!

 

The motor mounts will match up, but you will need to use aftermarket accessories, or the LT1 Corvette accessories.

 

Too much work for too little gain, IMO.

 

If you need help, feel free to check out my website...listed in my sig.

You can ignore aklim. If you search through the 3rd Gen section or check it out frequently, you will see that he posts merely to increase his post count, as he will often times post in 10+ threads in a row, most often offering next to nothing as far as content goes, as he displayed in this thread.

Eric

 

Like I care about my post count. I will the day it starts paying me some good money. Some of us have jobs that have time off for injuries and have time to post here on certain days. I'm sorry that your job requires you to be there even if you have a broken bone or sprained ankle and cannot move beyond the computer easily. So I post in 10 threads. What's your point? You need to flame me even in this forum? I was not aware of the limit to posts. I was expressing an opinion that maybe you didn't like but I could care less about your opinion.

Fine, if you want to get into it, what will the trouble of shoehorning an LT1 get you besides the novelty? It is a reverse cooled engine which needs a totally different ECM and probably harness. So, I have dropped 2 engines into my car which are L98 and have had no problems to contend with. They are both 350 displacement so the potential is about the same. If I am wrong please show me the dyno charts that show the LT1 making so much more power WRT an L98 when you are comparing apples to apples. Sure, stock they might make some more power but we already knew the L98 intake sucks. Modded they don't make that much more than the L98. BTW, this is not coming from me but 2 professional engine builders who do both. Modded you might get 20-30 HP more out of the LT1. If you were in a race where the purse is say 100 grand, sure I would do it. However, to go thru the trouble for the street where I am not really racing for money, is that 20-30 HP going to pay off for all the trouble. Now, if you think that LPE doesn't know what it is talking about, please tell me that you know more than they do. I need a laugh for the weekend.

Please show me that I can get say 100+ HP out of the modded LT1 that for the same money and effort that I cannot get out of a similarly modded L98 and I will be running around trying to shoehorn one in. How do you make more power out of the same displacement unless one is so hopelessly inefficient than the other and I don't see too many tuner shops that can tell me that they can get way more power out of the LT1. Please show me a dollar vs power chart to say it is more worthwhile. Don't add your own personal labor into in but compare what it would cost being sent to a shop to do so wecan compare apples to apples.

Maybe you'd feel better about me if I brought the car down to your stupid church, held hands with the pastor, prayed for devine guidiance before I commence work and had an LT1 to stuff in it? Or would you prefer that I held 2 engines out there and ask for a sign as to which I should install?

 

LT1 with decent exhaust, looking at 300HP without breaking a sweat. Consider the 150 HP 305 it would be replacing, seems like a reasonable swap. Wiring gets complicated if you use the factory harness, and the AC compressor is in the way I think, notch required at the frame.

 

LT1Powered85Z


how much did the swap run you..

 

Hey Aklim,

Port a set of stock LT1 heads, change the cam, and reprogram the PCM and you're looking at high 300's (some are at 400+) at the wheels for under $2000 bucks. What kinda $$ would it take to put an L98 at that level and still net over 20 mpg?

 

12 hrs to R&R cam or so the books says. Reprogram the ECM with a dyno is about $500. Camshaft is say about $300. Gaskets required abbout $50. Now we are talking about porting the stock heads. CNC porting of LT1 heads per LPE is about 1900. For that kind of money, I'd go with a set of race ported AFR heads. If you get them used, it could be about $1000. I would say under 3000 you could do what you want with 20 mpg. I cruise 300 miles on 14 gal of gas with 3.73 gears. If you optimize the system to all work together, ie buy a package that someone has used to get the power, 300-400 is attainable although I would say mid to high 300s. If you mix and match, well.....

When I went to 4.10 gears I got 200 miles on 14 gal of gas whether I cruised or drove in the city. Of course, you could get more MPG by going with lower numerical ration gears like 3.23 but I am not sure if that would work with your cam.

 

Like he said....He is switching a 305 to a LT1 (350) It is way worth it. Why go for an older L98 when he can get this cheap? No way is it to much work for to little gain. Ill help him put it in

 

So why are people who do this sort of thing professionally tell me that the best that they can get out of modded LT1s vs L98s are about 20 - 30 HP?

 

Hey alkim dont know why you are paying 1900 for ported heads I gave a local machine shop 500 to port my lt1 heads. They still have the stock valves and flowed over 240 cfm. now had a cam and run 11's I myself have already ran 11.4's and have now upgraded to full lentgh headers and a better intake so I cant wait to se the difference that makes. Anyway show me a stock headed 350 tpi with no nos or supercharging that can lay those kind of numbers down. Hell you wont find a hand full that are supercharged or nos fed that run those kind of numbers. So saying that a l98 with stock heads can make with in 30 horse to a lt1 is crazy. Or if they do they sure dont show it at the track? I would highly recommend going with the lt1 unless he just likes running slow then I would recommend the l98

 

I must get some deals on my stuff.

Cam... $250

New Springs, locks, retainers... $85

Gaskets (including head, intake, timing cover gaskets and seals)... $115

Professional port job for heads (those are hand ported, not some generic CNC program)... $1000

New timing chain... $30

ARP head bolts... $50

Comp Pro Mags... $250

Oil and filter... $35

Coolant... $8

Programming... $80 plus shipping from Ion

Labor... Free cause I can do it myself

Total... $1895

I actually spent less cause I got my valve train stuff on a group purchase and I can program my PCM myself.

BTW, I've never seen a stock bottom end/stock intake L98 break 400 RWHP, I've seen several LT1s do it though.

 

I just took the figure off Lingenfelter's website which was 1900 for CNC ported heads, the details you can read about at his sitehere. The L98 heads are comparable in price and work.

What I meant was that the block being a 350 in either case and if you went ahead with doing the same mods to an L98 as you would the LT1 (heads, cam, intake) you would be about 30 HP apart. I asked around about stuffing in an LT1 a while ago and their consensus was to build up the L98 unless 20-30HP would be meaningful. Now, a stock LT1 is probably a litle quicker than a stock L98 however, my question is where you think the power would come from? Is the efficiency of an LT1 worth that much in terms of power to justify the time spent on making it work? If I had a shell of a car and the LT1 sitting around doing nothing, I might be tempted to try it but what they are saying is that a modded L98 and a similarly modded LT1 will not be that far apart.

Edit: OK, I'll bite. Lets use the car in my sig and tell me how much power you think I'll make vs a similarly modded LT1