Hi Guys, Noobie here with a general question about choices. A little background for starters. I have a carbed 350 that I want to convert, thats in a 4X4, so think in terms of DD/ under 3500 RPM 99.999% of the time. I've been reading up as much as time allows, but still lots to learn. I have gathered some parts, mainly the TBI system ( harness, PCM # 16197427 ) and motor out of a '95 Suburban. What I would LIKE to do is set it up as a fuel only system, as I bought a NEW GM HEI from Jegs last year and it has 4000 miles at most, compared to the 224,000 that is on the '95 motor/system. I've seen on DIYAutotune"s site a fuel only setup, but they were running a Mega Squirt system ECM. Can the '427 be modded to do the same? Theres some other install issues the MS system could eleminate ( according to e-mail questions ) like having to have a VSS. Do you Guys feel there are some better options out there I might not know about? My thoughts are to get the system lined out on the motor thats in there now, and go thru the '95 350 next year. Present motor- late '70's 350, Comp XE 256X4 cam ( 210/218,.447/.462, 111LC ), 600 Holley on Edelbrock EPS man, headers w/dual turbo muff's. New motor will be- '95 350 w/ Swirlport heads, Lunati single pattern ( 207/207, .437/.437, 112LC ). My normal hiway cruise RPM is 22--2800 depending on traffic. What say the collective wisdom here? This has to be as low buck as possible, this will give me something to do until spring. Or plant closed up and is moving, we got the 'ol " grab your ankles, here's your Xmas Sausage :( " the 23rd. Any/all opinions welcome. Thanks Guys, Al

This sounds like a fairly conservative engine. And since you are stressing "as low buck as possible", then I would say - stick with the 600 Holley.

Honestly, you should be able to get the carb running silky smooth with either one of those engine setups you mention. If the carb has no choke, then install an electric choke and spend some time tweaking it. Then she'll start and run just fine in cold weather and all the way through engine warm-up.

It's not like you're gonna gain horsepower with the EFI. Yes, you MIGHT gain some drivability with the EFI, but I think if the carb is set up properly, you'll never notice the difference. My vote - stick with the carb!

Good luck if you switch to EFI. I switched to an Accel DFI and it was MUCH, MUCH more work and money than I thought it would be.

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Let me just tell you man this is alot of work that will not benefit you. A carb is your best bet.

The VSS and so on isn't that big of a deal and since you have a 95 engine and controller the sensors on the engine should all work. Your main issue will be tuning and if you have limited to no knowledge on that good luck. The pre LS controllers are nightmares, not only to find the software logging and tuning but to get dialed in nice. Not to mention trans calibration. Alot of things will have to be deactivated and turned off your best bet is to find someone familiar with the PCM side that is STEP 1.

Engine will have no problem talking to controller. Nothing else should be needed and cam looks conservative enough for the PCM to handle, it could probably self learn but I don't know if I would risk it.

I'd put the TBI on.

As far as nightmares, I guess those who have done LS based systems might think so, but the fact is there is an entire aftermarket (on the web) to choose from to work with those TBI, TPI, and LT1 systems.

One big stumbling block with tuning is these are EPROM cpu's, not flashable memory. To make a new tune you have to be able to burn it to an EPROM and plug that into the PCM.

One way to get around this is to buy a Holley Harness and commander 950 cpu. Direct plugin to everything, laptop tuning, no VSS, and optional wideband, for not much over $500. I've seen them used on ebay almost free.

A lot of 4x4 guys have done what you're describing. the 2bbl TBI will do everything you need. Advantages include smoother running at all rpm's, smoother throttle application, and the ability to operate properly at any angle.

Micheal (radcannon) is highly respected (deservedly) and has done some great stuff, but IMHO his "my way or the highway" attitude in regards to anything that is not LSx based is inappropriate.

Fact is, 99.9 % of the "hot rod" world (counting non-gm) is NOT and never will be LSx based

As said, for driveability, TBI. But, you should get as much as you can from the donor vehicle to install onto the '95 engine. Including the dist and knock sensor if you stay with the GM ECM. Keep the present engine until then.

If GM ECM is used, you have to have all GM system.

Otherwise, I agree with JimM and get a Holley Commander 950 and learn to program. At their website, I believe Holley has starter programs to get one going.

There are some controllers/systems are Plug & Play, they learn while you drive after you enter engine/vehicle parameters. I want to say, FAST EFI? and XFI?

I'd put the TBI on.

As far as nightmares, I guess those who have done LS based systems might think so, but the fact is there is an entire aftermarket (on the web) to choose from to work with those TBI, TPI, and LT1 systems.

One big stumbling block with tuning is these are EPROM cpu's, not flashable memory. To make a new tune you have to be able to burn it to an EPROM and plug that into the PCM.

One way to get around this is to buy a Holley Harness and commander 950 cpu. Direct plugin to everything, laptop tuning, no VSS, and optional wideband, for not much over $500. I've seen them used on ebay almost free.

A lot of 4x4 guys have done what you're describing. the 2bbl TBI will do everything you need. Advantages include smoother running at all rpm's, smoother throttle application, and the ability to operate properly at any angle.

Micheal (radcannon) is highly respected (deservedly) and has done some great stuff, but IMHO his "my way or the highway" attitude in regards to anything that is not LSx based is inappropriate.

Fact is, 99.9 % of the "hot rod" world (counting non-gm) is NOT and never will be LSx based

Ya you are right Jim, sorry about my attitude sometimes I just think there is better bang for the buck in alot of applications but that is not how I meant to come across on this application. Just being a basic streetability application for a DD.

I am just trying to make him aware that the hardest part of the swap will be the tune on that computer, everything else should be straight forward. The PCM interface just is really not user friendly and this is the number one reason I stay away from it. I hate flashing a tune everytime I want to change something, also it is very easy to kill the PCM's. I would also say go aftermarket on the controller, I think it will save you trouble in the long run, if you are tuning it yourself that is if not the stock system will be fine just find someone knowledgable about your system to take care of all the things you need to turn off to get it to run properly.

The GM computer can "auto tune" too, any computer can. The only thing is that the base tune has to be close enough for the PCM to learn in. Basically it can change fuel trims but stock PCM's limit the amount it can change fuel trims, aftermarket PCM's should do this too although the might not be limited which would really scare me. For example if an O2 sensor went out and the aftermarket system was completely "self-tuning" if would keep dumping fuel in and definitely cause damage. The basic ability for it to adjust though is why the base tune on the PCM might be able to control your mild cam but you still need sensors and codes turned off.

The OP said "This has to be as low buck as possible". To me, that's the most significant statement in his post. That's the main reason I think he should stick with the carb.

Given enough money, anyone can install virtually any kind of EFI and make it work. I was rudely awakened when I installed my Accel DFI. First, there was the initial cost - about $3,500. Then, I couldn't really do any tuning without wideband O2 sensor - another $1,000. Then I hired a guy to tune it for $200 - he sucked. Then I hired another guy to tune it on a dyno for $800. It was better, but still not right. Finally, I got exasperated and called Accel. They sent me a base program and I learned how to drive and tweak the maps myself in real time.

I figure my total cost ended up being about $6,000 to do EFI, which was WAYYYY more than I had planned on. So when the OP posts about budget concerns, I think he needs to be aware of the potential for cost over-runs! ;)


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The OP said "This has to be as low buck as possible". To me, that's the most significant statement in his post. That's the main reason I think he should stick with the carb.



I completely agree with you, and this is coming from someone who recently installed a new FI system on his car. I did it because I was curious, I do some varying elevation drives in my car that cause some carb issues, the net cost to me was less than $1000 since I was going to need a new carb and dyno time anyway, and I had some extra money burning a hole in my pocket. Given everything he said he's going through right now and based on the fact that the truck seems to be mainly highway driven with no offroading, I couldn't in good conscious tell him to go with FI. Look at my past and Lord knows I'm certainly not the best person to tell someone how to use their money though.....

However, given that Al already has some of the parts put together I guess it could go either way.

DAM! I forgot I posted over here :(, asking for advice. A little update- I've gone thru the harness eleminating LOTS of wires, for the most part tranny related ( I'm running an SM420, 7.05 1st gear ). I've spent way to much time at TGO reading up on these P4 PCM's, as theres a few Guys running them, and have done the mod's. I have downloaded Tunerpro, playing with it to get a feel. I'm at the point money wise ( NOT counting the HP fuel pump ) to go EBL from Dynamic EFI, or spend some money at Moats for some tuning tools. Bob at Dynamic even suggested some stuff from Moats, over his EBL, that would work with my newwer PCM to save a few bucks. JimM nailed it. Besides the overall driveability improvement, its the off camber stuff that I want to improve. On my Holley, I added spring loaded needle/seats, extended vent tubes, lowwer fuel level in bowls. Last time out was 9hrs of hell with the carb problems I had. It got to loading up so bad at times it couldn't pull itself up ledges, or over a rock when the ground got rocky like a creek bottom. To much bouncing/rocking. The truck is a Toyota Land Cruiser, that pulls a small Military trailer loaded with our camping gear. We get to camp, drop trailer, and run trails, some of which are SUPPOSED to be intermediate but often times are not. That was the reason for the under 3500 RPM comment. Thanks Guys for the comments. Al ps- to the one poster wondering what parts I had to work with, I robbed EVERYTHING under the hood when I got the complete running LO5 350. Wiring harness, fusebox, anything that that could be used for something else. Had to get my $300.00 worth :D