My friend is looking at putting a 350 in his 91 RS. It is a throttle body 305 currently. For the time being at least, the plan is to leave it throttle body injected. The motor that he is getting is out of a late 80s truck. He can get the throttle bodie injection system with that too, but he has not asked about wires and soforth. My question is what all will he have to change to make it work properly. The plan is to use the injection setup that is in his car now so that we dont have to figure out how to make all of his gauges work with a different harness, and so we dont have to change wiring harnesses. I know he will need probably new inectors(I wondered if the ones that are on the truck would work. He will also, need a knock sensor an if possible a new chip. What else will he need? Also, do you have to follow about the same guide lines for the cam in a throttle body car as a tpi? I dont necisarily mean with the rpm ranges and soforth, but rather whether you have to use a cam that is specifically designed for computer controlled vehicles. Thanks for your help.

Ben

 

What is the part number of the computer on the truck? If it's a 7747 it'll plug right in where the 8746 is right now. I would use the truck's computer, chip, and injectors. I've heard conflicting reports about the knock sensor, couldn't hurt to get a new one though.

 

Thats what we would like to do, but my friend has to talk to the guy again. It is still in the truck and running. Where abouts woud the number be on the ecm? I told him to see if he could get computer and all. Does anyone know how much power these put out? It is in a 1 ton truck. Late 80s but not sure exactly what year but can probably find out.

Ben

 

The trucks injectors will work. Any TBI injectors will work but it's good practice to get injectors from an engine with similar/same displacement.
The wiring harness has nothing to do with the guages, the oil pressure sending unit and the 3 (yes 3) coolant temp sensors all screw into the same place on the 350. They're both small blocks so the external dimensions are same same, no difference and this is the beauty of chevy.
A 350 knock sensor is a good idea. This might not be needed but I would get a knock sensor for an 89-91 caprice with the 350 if you're going to be using a roller cam. If not, go with an 87-95 truck 350 knock sensor.
Getting an ANLU eprom from an ~89 caprice is the best stock eprom for just about any 350 TBI in a ~3500lb vehicle. E-mail me if you want/need sources for the eprom. You can always spend $250 and have ALL the equipment to burn your own eproms! It isn't hard, everything is visual, nothing is complicated and it's a lot of fun, same as tuning a carb only you have MORE control over everything (idle speed, Air fuel ratios, fuel tables vs. manifold pressure, spark parameters and tables).
TPI/TBI same thing when it comes to cam selection. Any speed density or MAF efi system requires decent vacuum which means you can't get like a 108 lobe sep cam with huge duration and lots of lift. speed density (TBI and the 90-92 TPI systems) are very sensitive to changes made by cam swaps and exhaust/intake work. They have everything that a MAF system haves minus the ability to measure the amount of air entering the engine! This means that the "self-adjusting" on a SD system is minimal and even non-existant under heavy pedal situations. This is why I think you/your friend should invest the $250 and do yourself a favor with burning your own eproms. Like I said before, it's all eye candy now, you only need to know a few things to get a really good eprom (spark counts and watching the ecms BLM, aka learn multiplier).
Everything above depends on the cam you guys want to use. A huge computer friendly cam will require a custom eprom to behave on the street and it'll also require fuel pressure or bigger injectors than even the stock 350's!!!
Let me know what kind of hp you're looking to make and if it's a roller cam or not.

 

Well, If it was going to be my car I would invest in the stuff, but I am going to be running a ccc which they dont make the stuff to program. I know someone with the stuff to program chips though and I thought I might ask him to help me out to at least get the car running good. The motor is coming out of a truck. When did trucks go to roller cams? He is not looking to go real wild on this one. He said that his uncle is going to help him port the heads. They guy who he is getting the heads from also had a set of older heads (I think 75) and I suggested that he might want to see about getting them depending on exactly what they were because there would probably be a good chance that the truck would have swirl ports. So he is going to rebuild with possibly slightly higher compression and port the heads, but I dont think he has decided for sure if he is getting a cam. I dont think he is doing his exhaust yet either, but I think is planning on that down the road.

 

So does anyone know what kind of power these made stock? How much do you think putting a set or ported heads on it would help? Oh and can he run anything other than the stock cam with the stock computer from the 350? I dont know that he is even going to put a cam in it though. Well, the reason he doesnt know how much he wants to do to it though is because he has a set amount of money he is planning on spending right now and he wants to see how much he will have left after he gets his car painted. Thanks for the help.

Ben

 

I believe the L05 truck motor made 210/300. And ALL that power was made under 3800 rpm.

 

Ouch. Are there any cams that he could run with the stock chip. What kind of cam did the caprice have in it? If the caprice had a bit bigger cam we might be able to have that file burned on a chip.

 

Also if we were to use an aftermarket cam, what would be suggested for this motor. We dont want anything too big. It would be nice if it would run with the stock chip or with modifications we could make without a scan tool, because I am not sure if I know anyone that has the software for his car. Are there any free programs that will scan the tbi vehicles? Also would they require the same connector cable as a 87 tpi? If so that might get us on track.

 

Dude, where have you been looking? There is a post about the free software that's "stuck" at the top of this forum!!!

 

Sorry about that. I didnt really look through this forum. I did a couple of searches, and asked this question but have only been coming to this post through a link in my email notification. I will check that out. So will the same cable tha works to connect to a maf tpi car work or is it different?

Ben

 

I believe the part # for my cam and the L98 is the same, roller cam, pretty mild, but not as mild as the L03 cam. My L05 was rated at 205hp @ 4400rpm and 300lb-ft @ 2400/2800rpm (depends where you look) stock.

 

Yeah, I might have to talk him into a cam of some sort. Did the what year did the trucks go to roller cams? What would be suggested as a cam? As a recap of what he will be doing: The heads and probably intake will be ported. He will be doing a rebuild so a suggestion on compression ratio would be good also. Unfortunately unless he has more money than he plans left over I dont think he will be getting headers or exhaust but he doesnt have a muffler and Maybe not a cat.

Ben

 

TBI trucks never used a roller cam. The L31 starting in 96 was the first year (Vortec). I like the LT1 F-Body cam and I don't know about going much over that (like ZZ4) for a daily driven TBI vehicle. I have an LT1 F-Body cam myself (from a 96) that I think will wake up my L05.

 

No truck LO5's are roller, only 96 up Vortec trucks have a roller cam. As far as a cam, if he is sorta not straying far from stock a Crane 2030, or a Comp CS 260Ah-12 are pretty good and should work fine. As far as compression I would stay around stock, which is about 9 to 1. You can run as high as 9.5 but then you are getting into a premium only situation especially with iron heads( Vortecs can handle about 10 and be ok on premium fule though).

 

do you have the specs on either of those cams?

 

Wellllllll....my L05 is 9.8:1 stock, according to the Michigan State Patrol test file. No octane requirement.

 

I doubt it, mine is 9.3 :1, just because it is a cop engine doesn't mean it has higher compression. Besides let's say it does, now with crappy 87 gas that computer is backing out enough timing that the engine isn't making all that much power anymore. With 9.8:1 or for all intensive purposes 10:1 you shouldn't run garbage fuel regardless. The cams spec at 2030- duration-264/274' lift- 423/446. Comp-260/260 duration, lift-444/444. The crane is a dual pattern cam and there is a step down comp and it has less lift and duaration on the intake and the sam on exhaust however I have a friend with that cam in his truck and it didn't make any difference(the Cs252AH), but i think the 260 would work nicely.

 

Thanks for the help. This gives me some ideas on what we can do with his motor at least.

Ben

 

I have the data file right here. Would you like me to send it to you? It says my L05 is 9.8:1 (police package) and the L03 in the Caprice (also police package) is 9.3:1. It's NOT a cop thing, but an L05 thing. The civilian L05 used in the 1A2 special service wagon (only 180hp, like the civilian caprices) is also 9.8:1, fyi.

BTW, I *ALWAYS* insist on Mobil 89 octane.

 

I have never seen a civilian rating on the LO5 as 9.8:1, that is higher than the current Vortec motors. I have seen all LO5's rated as 9.3:1, regardless of being a passenger car motor or in a truck. Maybe they are higher in the cars, but I don't think so, sounds like someone misprinted with an 8 instead of a 3. My trucks LO5, is 9.3:1 and that is a fact, as far as 9.8 sounds like a misprint. All truck LO5's are 9.3 and as far as the cars other than a roller cam everything else is the same making them 9.3 to 1. Maybe you should chack that file with GM, I have talked to them and they say 9.3:1, 9.8:1 is similar to the LT1 compression wise and would come with an octane requirement if it were true. The current Vortec truck engines are still at 9.5 to 1 and the LSI car motors are at 10 and require premium fuel. I can almost guarantee that your LO5 is like eveyone elses, 9.3:1.

 

Ok, here is more data from the MSP test data.
89 Caprice L05 was 9.3:1.
90 Caprice L05 was 9.8:1 with a 5lb-ft torque increase. Sounds reasonable to me. The 4.3 and L03 were always 9.3:1. And 90-93 Caprice L05s were 9.8:1 and power was NOT always the same. I'm sure there are people who will back me up, but this isn't entirely relevant, though your reluctance to believe a reliable source frustrates me.

 

2 things that don't make sence to me is that they're built with the same parts no matter what year. The ONLY difference might have been a simple gasket change but even then it isn't worth .5!!
If they had changed the heads or pistons then it wouldn't be an LO5 anymore, hence the reason why the LO3 isn't a LB9 and such.
I've heard of some of the "heavy duty" trucks coming with less than 9:1 compression so I'm not doubting your sources, I'm just completely confused. Makes you wonder if by accident they installed flat top pistons on one side of the engine and dished on the other or if they used different head gaskets on each side!
It wouldn't suprise me if there were a few lemons.
What we need is somebody to take their car over to car-craft and have them rip the motor apart and measure the compression ratio. That's not going to happen so let's just let this topic slip off the edge of the earth and forget about all the 9.8:1 LO5's .

 

I will continue this privately.