lt1 intake conversion

[thirdtimevetteowner]

Can anyone tell me if doing an lt1 intake conversion on my virtually stock L98 is worth the $ and time spent to install it? I found one w/the smaller distributor, intake, fuel rails and lines, powder-coated to the color I choose for $550, shipped. The price seems good to me considering what a mini-ram costs, although I know the lt1 is NOT a mini-ram. I plan on installing Hooker SC's, true duals w/Random Tech hi-flow cats and x-pipe and Flowmaster mufflers soon. I may be installing a cam at the same, so any advice on a particular grind would be appreciated. I also intend on doing a torque convertor swap (somewhere around 2500 stall), to help launch because of the pathetic 2.59 gears they put in it. In the old days, 3.07's were the pits. I can't believe they put such crappy gears in a Corvette.

Rich K

P.S. I know some of you like the 2.59's, but it is beyond me as to why. I nearly had a Dana 44 w/3.45's but the deal fell through. And I know the L98 is all about low end torque and I will lose some w/the intake swap, but I like high revving engines, and will deal with the torque loss w/gears, eventually.
So basically, I am asking if anyone has the lt1 intake and how do they like it?
Thanks to all who reply.

 

[Mad-Mic]

i'm doing this same conversion and have talked to many others that say its well worth it. i will comment and talk to you about it later tonight when i get home.

 

[speedmaster4]

did it...love it...night and day difference...i was prepared to loose a little low range torque in exchange for higher end but if anything the low end is better now and top end is much stonger

do a little extra 'lightening' of the lt1 mfld and keep your orig dist...the 'little' dist seem to be less dependable

 

[Mad-Mic]

my plan is 3200 stall stick with the 2.59 D36 388 sb with 150 shot and my LT1 intake ZZ409 cam. got everything besides the heads for the whole swap. gears will motivate the rear tires and the shot will pull the gear

 

[tigmaned]

will the LT1 intake only work on L98's with aluminum heads? i have a early 86 with the cast iron heads. but was thinking about doing the change too.
any body thats done the swap have it dyno to see what kind of horses there pushing now.

 

[thirdtimevetteowner]

mic,
are you still running the stock 113 heads? Or have you replaced them, or ported them? I don't want to get that far into mine because as soon as I see those dished pistons I'll want to do a complete rebuild, just like what happened to my 72 Nova SS motor....lol

 

[Mad-Mic]

will the LT1 intake only work on L98's with aluminum heads? i have a early 86 with the cast iron heads. but was thinking about doing the change too.
any body thats done the swap have it dyno to see what kind of horses there pushing now.

you can use any SB1 head you want. BUT your not going to see much gain and alot of loss in torque if you don't do a heads and cam setup.

 

[Mad-Mic]

mic,
are you still running the stock 113 heads? Or have you replaced them, or ported them? I don't want to get that far into mine because as soon as I see those dished pistons I'll want to do a complete rebuild, just like what happened to my 72 Nova SS motor....lol

i don't have D113's but mine are aluminum. 113's started in 88 mines an 87. i'm going to go with an aftermarket set of heads most likely.

your 113's with alittle work and a good cam would produce 360 rwhp with the mini ram and about the same in torque at the wheels.

 

[KANE]

you can use any SB1 head you want. BUT your not going to see much gain and alot of loss in torque if you don't do a heads and cam setup.

Here is a great site-

http://www.lt1intake.com

There are a few ways to do this. According to what I have seen and read, your BEST BET with an LT1 intake swap is to actually use an LT4 manifold with fastburn heads.

So, out of all the heads on the market... you can take your pic but the Vortecs won't work.

The problem here is with the Vortec head design- the ports sit higher than the standard heads. That means the LT1 intake WON'T fit.

Want to see dyno results? Here is a link right off lt1intake-
http://lt1intake.com/files/dyno_Samuli.htm

SUMMARY FOR A 1987 TRANS AM:

​

-Stock bottom end​

-Stock iron heads, gasket matched and 30 cut out valve job​

-Stock throttle body bored to 52mm​

-K&N filter (RC-5000)​

-Comp Cams Extreme Energy 224/230 112° LSA (08-503-8) (LT1 intake only)​

-Flowtech headers and y-pipe​

-Edelbrock cat back without cat​

-MSD 8.5mm plug wires​

-Accel ignition module​

-Haltech E6GM (MAP)​

​

Here was the outcome-

52 rwhp more with the LT1 intake and 224/230 cam than earlier with Accel runner / manifold and zz4 cam. Only 16 ft/lbs torque was lost.

Here is the guide from John Millican-
http://www.lt1intake.com/files/swapping.htm

 

[thirdtimevetteowner]

Thanks for the input, Mic. It is much appreciated, as usual. What do you think about an lt1 motor w/50 miles on it for $1100? It came from a dealership car that had a fire. There is no harness for the injectors (which are slightly melted, also the dist. cap is singed), but everything else is there.
I plan on going to look it over carefully this weekend. Anything you can think of that would make this a bad investment?

 

[Vettefan87]

i'm doing this same conversion and have talked to many others that say its well worth it. i will comment and talk to you about it later tonight when i get home.

Not to hijack the thread, but what happened to the procharged 96 Mic?

 

[Moonunit 451]

my plan is 3200 stall stick with the 2.59 D36 388 sb with 150 shot and my LT1 intake ZZ409 cam. got everything besides the heads for the whole swap. gears will motivate the rear tires and the shot will pull the gear

How much do you think the 2:59's are gonna take Mic? They granade all the time. I'm surprised with your 60' times as often as you run you haven't taken it out yet. I don't know how you get those times and 60's, but I can't imagine the rear lasting long in the mid or low 12's.

 

[Mad-Mic]

Thanks for the input, Mic. It is much appreciated, as usual. What do you think about an lt1 motor w/50 miles on it for $1100? It came from a dealership car that had a fire. There is no harness for the injectors (which are slightly melted, also the dist. cap is singed), but everything else is there.
I plan on going to look it over carefully this weekend. Anything you can think of that would make this a bad investment?

what are you buying this for? your 89 and put it in? if your thinking about swapping an LT1 in save your money and do a built stroker shortblock and get your D113's reworked and a good cam along with the LT1 intake *setup* and make 100+ rwhp than just putting that LT1 motor in the car. it will probably cost less after its all said and done to go with the stroker setup.

 

[Mad-Mic]

Not to hijack the thread, but what happened to the procharged 96 Mic?

of friend of mine owns it. getting some personal things straight before i can buy it. it's not going anywhere.

 

[Mad-Mic]

How much do you think the 2:59's are gonna take Mic? They granade all the time. I'm surprised with your 60' times as often as you run you haven't taken it out yet. I don't know how you get those times and 60's, but I can't imagine the rear lasting long in the mid or low 12's.

Colin,

I'm not real sure how much it will hold but i found alot of hope at the track over the last few years. a guy i know from the local track has an 85 C4 with 383/SR/ZZ409 cam/AFR 195's/Full Bolt'on's/3500 stall/MT ET Streets/skinnies slick combo at our local track running 11.7's untuned for 100's of passes on a stock D36 w/ 3.07's. i know he's one of the lucky one's. i just think with the 2.59's if i can stay low 1.7's maybe a high 1.6 60' time every once in awhile on 315' DR's she'll hold due to the ring gear being so fat and big, having the over lap in teeth that it won't break as easy. from what i gather is the 3.07 gears only have a 2 teeth gap over from ring and pinion gear mesh. i never found information but the gap over on the 2.59 must be atleast 2 if not close to or maybe 3 over. if so it's a stronger setup let alone the torque divider being it's a slower gear. in this theory with a 3200 stall LT1 intake and a 150 progressive shot ( a little black box programable for the % from start of cycle and the length of time to it's 100% flow) on a 406 making 450+ rwhp NA and 600 on the bottle but coming off the line having the window switch at 3500 rpm at 20% of the 150 shot for the first 3 seconds the the whole 150 shot. this will be into 2nd gear when the shot fully comes on.

if all goes well this will be the first 2.59 geared car in the 10's

if it breaks it breaks and then i take my happy @ss upto contemporary corvette outside of philly and buy a 3.45 geared D44

 

[Mad-Mic]

here is some pics of a forum members LT1 conversion to give you more of an idea of what he did to get it to work with Vortech heads. the general info and the pics will also work for SB1 heads.

The external thermostat housing is bolted onto a bracket that I welded to my air pump eliminator bracket. I used the stock top hose, just shortened it a few inches. I drilled several small holes in the thermostat to make it easier to get the air out when filling with coolant. I've driven the car about 600 miles, much of it in 100*+ weather and stop and go traffic. Temperature never went above 200*. Thermostat is 180*. Never had to add any coolant. Still in the tuning stage but the car feels very strong from idle up to 5000 plus rpm's. It is an automatic with stock converter which in 86 was about 2000 rpm's I believe. Anyway, most comments I have heard about the lt1 intake conversion were negative because of the remote thermostat location. I think this works out great on a corvette motor....The motor was a 96 vortec out of a 1 ton truck. I bought a summit engine kit with .030 over pistons. The truck motor had a roller cam and pm rods and four bolt mains. I had the block bored amd decked, Had it all balanced, had the vortec heads machined for more lift and bigger springs. I modified the lt4 intake to fit the vortec head bolt pattern. Used a hotcam and lt1 injectors, long tube headers with no cats but I still have stock pipes and mufflers. The only original TPI part is the throttle body. I want to install a new exhaust system and 1.6 roller rockers next, but the wife is not happy with me now for spending too much money. Besides, I don't want to break the Dana 36 that is in there now.

I originally built the motor to replace the TPI 305 that I had in an 85 s-10. But since the stock 91 305 could smoke the tires all the way through 2nd gear, I decided to find something else to put it in. Then I found the 86 Vette with no motor.

Don't know how much HP it is making but it is fun to drive. Still has plenty of low rpm torque and should wind up to 6k with no problems. And the best thing about the ltx manifold is you can pull the injectors in about 5 minutes.

i think it came out looking sweet! doesn't look to hard on the installation either!