Hello fellow gearheads!

I'm new to the board, so a little about me: live in Seattle, WA and currently drive a 90 9C1 with ~245K on it. Looking to replace it with something new soon. I stumbled upon this site while doing research for my project car. I'm currently weighing the pros and cons of different engine/tranny choices and am trying to come up with a realistic budget or estimate for the LSx option.

The recipient is an 87 Caprice (b-body). The goals are a daily driver that runs on 87 octane and passes a tailpipe test (granted for 87 it's pretty loose). I was thinking perhaps the 6.0L truck version, stock, would suit the bill but I'm not adverse to cam swaps, torque convertor swaps, intake swaps, etc. if they are a proven combo and the programming isn't difficult for a reputeable tuner to provide for me remotely (i.e. without needing a dyno-tune).

So, if anyone happens to already have a rough spreadsheet of costs that they are willing to share I'd greatly appreciate it.

FYI The other engine choices I'm playing with are a Ram Jet 350 (with the MEFI4 controller and O2, but it requires 92 Octane and I'm not sure about the smog on it), the 8.1L big block/4L85E combo from a Suburban/Avalanche and I'm open to other suggestions. I had considered the LT1/4L60E but for the trouble to get that in I thought I might as well go LSx.

Also, I currently get 25 mpg in my 90 with the LO5 350 TBI under ideal conditions on the freeway (maybe 13 mpg in town), and run about a 16.6 sec 1/4 mile. If I could match the mpg and drop the quarter mile to mid 14's (about the same as a stock LT1 Caprice with a good intake/exhaust) I'd be happy. If I could drop it to mid 13's, and still run 87, I would consider the project a total success. Sub-13, well... I don't want to get greedy :-)

Thanks for any help or advice!
Chris

 

Hi: Check JohnB's website he has a total breakdown for putting an Ls1 into his Monte Carlo it was about $9,000 total. If your doing a 6.0 truck motor these are a lot cheaper. There was one on EBay complete with accessories and computer and harness a while back for about 2K. Check S & P they have new mounts available for these swaps. IF you could use your existing transmission and get mounts to mount the motor in the stock location you could save a lot of money. Don't have to shorten the drive shaft, cooler lines, and linkage and could use the stock speedo. You allready have fuel injection so you don't need a gas tank and maybe the stock fuel lines could be modified. If the truck manifolds fit and you are only running a single cat you could make a Ypipe with a single magnaflow cat good for up to 6.2 liter and bolt it up to the cat backsystem. If all the truck accessories fit you will be OK don't have to to get a new bracket. IF you can get a truck motor cheap you might be able to do the whole job for about $4500 to $5,000. The biggest expense with these cars seems to be the exhaust system can run a $1,000 or more for custom duals and headers. Hope this helps. Good Luck.

 

Here is my cost breakdown:

http://www.corvetteforum.net/c3/70lt1/costs.shtml

 

I'll warn you right now. When you start with a budget, add about 50% to the budget at least because you will go over it. Is your current motor a TPI or TBI motor. Reason I'm asking is that the TBI lines might not work with a SFI injection.

 

You would have to get a different fuel pump for sure. Maybe you could run an external pump if you had to. I think the 4.3 TBI motor had a 2 piece 3/8 main line running down the passenger side up to the firewall and connecting to the back of the T/B. If this is the case you could use the Speedinc fuel rails with rear exit and bend and cut the the line to fit with a new fiiting on it. Where the existing fuel filter is mounted low near the rear axle you could mount the corvette regulator and fab up the return line and modify the rear fuel line. It should work no?

 

> If your doing a 6.0 truck motor these are a lot cheaper

I was thinking I'd go that route, yes. I've also started thinking if I'm putting all this money into the conversion I might as well get some decent power out of it. I'm sure there are some proven parts formulas to "massage" the 6.0L... cam swap, intake... yes?

> IF you could use your existing transmission and get mounts to mount the motor in the stock location you could save a lot of money.

Good point, however it's a 700R4 so then I'd have to deal with TV cable kickdown and related issues. Maybe it's not a big deal but it seems like it might be. This is another reason why I think maybe in the long run a Ram Jet 350 is easier and cheaper overall. I just need to find some real-world, candid opinions of the engine and even better some smog results.

> If the truck manifolds fit and you are only running a single cat

I'm hoping they will fit, yes. I have dual exhaust at the moment.

> Hope this helps. Good Luck.

It does yes. Thanks!

And Jeff - thanks for the cost breakdown link!

Chris

 

If I were you I'd just rebuild.. put aluminum heads on it and bump the compression up a little, some nice headers, better intake, and a slightly hotter cam. The raise in compression should help out your situation emissions wise and such. So long as you don't go overboard milage will not be effected, and could actually increase. Aluminum heads will also allow you to run a little more compression and still run low-mid gas. It'd also be tons cheaper than an ls1 swap. You also could consider doing some sort of aftermarket fuel injection system to try to help the gas milage even more. I don't see 14's being a problem if you stuck with your motor if you gave it a nice boost, and threw a little stall in there to get it off the line.

Peace,
Josh

 

I used to drive those for a living....fun cars (the 9C1's)

So where in Seattle do you live that they do tailpipe testing??

 

Hi Josh, I do appreciate the advice however I'm not convinced a TBI setup can deliver enough fuel to run even mid 14's. I might be able to get there with a 454 TBI setup. I will price out a rebuild (or maybe Gen1 crate long block) and see how this fares.

I was just doing some reading and ran across this article:
http://popularhotrodding.com/enginem...e/0409em_gmpp/
Now, I don't plan on going carb that's not the point. I just didn't realize how much power these engines were making with just a cam & spring swap. 500 hp - yikes! Gross, but still. And over 400 ft-lbs the entire pull (3500 rpm +).

How would the HOT cam be in the LQ4? And is this the same HOT cam used in LT1s? I'm familiar with some of those cam choices (HOT being a step up from the 845 cam iirc and a bit too much for a stock 350 LT1).

I live in Seattle proper, but I think anywhere in King County has to do tailpipe testing. It's easier to pass than AirCare in BC though (at least for my 90 9C1).

Chris

 

They do make high performance T.B. systems that'd probably be alot cheaper, and meet your goals. I just don't see any reason to spend so many thousands for such mild goals. FWIW: I do have a 4l60e for sale.. lol

Josh

 

IIRC, you can't use cams from a Gen III motor in your regular old SBC (LQ4) nor most any other part. As for the "Hot Cams" they are more designed for racing (road racing) then for street driving, although I know a couple guys who have gotten good results with them in their LS1's........there are FAR better cams out there, for your motor and the Gen III's then a Hot Cam IMHO.

I live in Snohomish County and have only been here a couple months but it is my understanding that there are some areas North of Seattle (not positive where) that don't have ANY smog tests at all.... I know mine is No Visual & OBDII check and that "should" be it.

Another thing to remember is that 99.9999999% of those magazine tests are done on an engine dyno (no car, just motor) and they are flywheel hp/tq numbers, not rear wheel. Not that I would turn 500 flywheel hp away mind you, just didn't want you to think that a carbed, cammed LS1 would hit 500 rwhp with no effort.

And I just read part of the article, it was an engine dyno, no car (with any of it's power robbing accesories on it) which tends to "show" more power then your typical "in-car" dyno showing flywheel numbers......still awesome though.

 

Hey Josh,

The 350 TBI I'm running currently has a bit of a cam (somewhere between the stock LT1 cam and the ZZ3 cam iirc) and I have a built tranny with ~2300 rpm stall convertor. I haven't run it at the track with this combination but with the stock heads it really peters out above 3500 rpm.

So maybe my goals are set a little low to warrant an LS1 swap - perhaps I should increase them :-) The LQ4 is 320 hp stock yes? So with a 4200 lb car that's probably a 14.5 @ about 93 mph. This was my original idea. Do the swap on the cheap with a stock 6.0 & tranny pulled from a truck.

However, I'm open to swapping the cam and putting in a higher stall. Maybe a few other little tricks. Suggestions? Any links to a thread discussing mild mods for daily drivers?

Chris

 

320hp is not very much.. a set of heads will do that and a slightly hotter cam. You could also do a TPI install on your car, with the LT1 intake manifold (drilled for distributor) . If your goals were like 13.0-13.5, I'd say swap to the lsx based motor. Otherwise you can easily do up to that with a decent stall, some nice heads, and a mild cam.. and still be emissions legal.. 375-400hp is pretty standard for a mild emissions legal 350 now adays.


Peace,
Josh