I have a 71 with a small block. I'm thinking of converting to EFI. I'd love to hear from others that have already converted. What manufacturer? What issues did you encounter? How does your car run now?

Any and all feedback is welcomed.

 

It all depends on your budget. Both time and money. What fuel injection? TBI, or port? OEM or aftermarket? The Holley Sniper is allegedly the best cross between inexpensive, durable, easy install, easy tuning and good power. An 89 GM TBI can be bought and rigged far and away the cheapest. But hardest tune-install. Least power and fugly too...

 

22 years ago I did a L98 install like off a 88-91 vette, speed density, so the air cleaner bolts right on the throttle body.....later on I went with a modified LT1 install....I have some parts left over from the L98 if you interested, runners, plenum, but no manifold or throttle body......make an offer if interested.....

speed density is far easier to plumb the intake because no mass air flow sensor.....I put the computer behind my map pocket it's a '72, later sharks MAY have an issue.....

see pix below.....

 

I installed the Holley Sniper on my 74 small block.The only issues that I encountered where both "Major". The first was a bad control module on unit right out of the gate! After Holley made it right with another unit the in tank pump didn't build up pressure and turned out to be a faulty pump and Tanks inc. made it right and shipped me another two days later.After those two issues were dealt with the car was running as good as expected. That was over a year ago. Just last month I upgraded the throttle with a progressive linkage and the car just flat-out got WAYY better! before that progressive linkage change the car just had too sensitive on take off and that resolved that! Overall I'm very, very pleased with the change!! one more thing I truly believe that the best way for me was to go with a in-tank pump on a FI ready tank!

 

I currently have the Holley commander 950 TBI system on my car from the late 90s, it works, its not as fancy as the new systems and the 600cfm tbi is good for like 400 hp, you could probablky find one of these for sale for fairly cheap since everyone is converting to the new stuff. I also have a Holley HP tbi system waiting to go on this car.

 

[QUOTE=redcruz1120;1599277078]I installed the Holley Sniper on my 74 small block.The only issues that I encountered where both "Major". The first was a bad control module on unit right out of the gate! After Holley made it right with another unit the in tank pump didn't build up pressure and turned out to be a faulty pump and Tanks inc. made it right and shipped me another two days later.After those two issues were dealt with the car was running as good as expected. That was over a year ago. Just last month I upgraded the throttle with a progressive linkage and the car just flat-out got WAYY better! before that progressive linkage change the car just had too sensitive on take off and that resolved that! Overall I'm very, very pleased with the change!! one more thing I truly believe that the best way for me was to go with a in-tank pump on a FI ready tank!



could you elaborate on the progressive linkage? I have a sniper on a bbc.

 

[QUOTE=Tiger Joe;1599277797]

This piece right here is the linkage. You need to remove the old piece and replace it in the proper position as per instructions to allow the primaries to open before the secondaries as opposed to the way it is from Holley where all four open at the same time. You will have to update software in system to the latest version too.. There is a Youtube video on this.

 

[quote=Tiger Joe;1599277797]

 

I just installed the sniper on my 427 car.

I had a 700 cfm holley carberator on it. It has a street/strip cam. Nice lope. 11 in of vacuum. After countless hours tuning on the carb I thought it was pretty good. Always a problem on start but good after warm. The car was very fast.

Now with the sniper I just had the best ride in the car ever. Install took a couple months. Side pipe car - so o2 was a challenge. Pump in tank - routing lines was a challenge. Had a regulator problem - Holley sent a new one (no hassle). Timing control with an msd 6al is next - vacuum advance currently.

1. So now turn the key it starts. Idles up for 3 seconds then down to 850 rpm (I have a manual trans). The AFR is monitored by the o2 and controls the IAC for perfect idle. It no longer has any fuel smell at idle! That alone is worth all the work!!

2. It will control timing too - once the msd 6al box is setup. Have to lock out vacuum advance first.

3. Drive-ability is way better. Power breaks run off vacuum. No drop in idle when breaks are pressed.

4. I know the HP is not any more. But it feels like more!! I can only go to 53% throttle (in 2nd gear) before back tires are spinning. First gear will spin tires as far as I want too. That is not new though!

5. Mostly know AFR is right so I don't have to worry about running lean when I ask for power.

6. It controls fans. Also steps up idle when AC is on.

This is hands down the best upgrade ever!!! Redcruz - Thanks for your encouragement. Question - how did the progressive linkage make you feel it was better? What do you mean by sensitive. Was it bogging?

 

[QUOTE=redcruz1120;1599278243]Very cool and great to know that this mod is available to install and firmware update is required to improve overall driveability. Thanks!

 

I went with the FAST EZ-EFI system on my 350.

1. Changed out:
a. Distributor, FAST runs the timing, electric fans, it increases ideal for AC, and added O2 sensor.
b. Baffled fuel tank, in tank pump and changed out all fuel lines.

I'm very pleased with the system and I have had no problems.

 

I plan on running the same tank and fuel pump setup as you, I was wondering what did you use for fuel lines?

 

-6AN Russell Twist-Lok Fuel Hose, Tanks Inc had everything, great customer service

 

I've had several variations:
1. Ages ago I had a Holley Pro-Jection (analog) with an external fuel pump. Amazingly it ran quite well for what it was. Not great though - it was essentially money spent to learn, but I had it on for about 3 or 4 years, ran fine all the time I had it. Was using external fuel pump so I had to keep it above 1/4 full or I'd lose suction going around corners.

2. Next I installed a RamJet 350 with the GM MEFI-3 (no O2 sensor). This time I installed an in-tank pump, 5.8L Bronco fuel pump, that's been great and I'm still using it with my existing EFI. Here is a link on that:

https://www.corvetteforum.com/g/album/6185062

It's been quite good, but if I were to do it again I would just use an 82 Fuel Sending unit and modify it to hold the canister-pump-assembly. The MEFI was reliable but there were no options to tweak anything and it always ran rich.

3. Then I wired a GM 730 ECM in parallel with the MEFI. I did this since I was learing to program chips in the 730 and if I screwed up, then I could swap over to the MEFI at any time. That worked fine and it was fun to learn programming and reading-&-writing chips, but when I found myself just running on the MEFI the last year, then I decided it was time to go with one of them "modern" self-learning unit.

4. Now I have EZ-EFI 2.0 running my RamJet 350. Once I got this thing put together properly it ran better than the GM 730 ECM (that I'd been messing with programming for years) the first day I used.
I chose the EZ-EFI 2.0 because it could be retrofitted to GM TPI systems (the GM 730 ECM system that I'd been using), I could use the existing fuel pumping system, I could re-use my MSD Tach Drive distributor & MSD 6a (had to lock out distributor for EZ-EFI conbrol of timing), and it seemed to be relatively simple to do.
It worked out pretty well

 

Had my Holley EFI Sniper installed at a local speed shop because I don't have a safe way to get under the vehicle. Overall it has been a good experience. No lag on acceleration, better cold starts. My install uses a return setup. I currently use vacuum to control timing. I did have some issues with the original 61 amp alternator not performing well enough at lower RPMs/idle, but that may been because it had a large pulley and/or just worn out. I upgraded to a better alternator and that stopped the voltage drops I was having which was messing with the EFI.

I also ended up with a hood clearance problem (LT1 hood style, I believe) which was solved with a shorter air filter, a flat filter lid, and a Holley Sniper drop base lower air assembly piece.

My pump is external and attached to the frame below the tank, and I have decided I don't like it there. It is very loud. I don't hear it at highway speed, but next year I will be switching to a new tank with an in-tank pump and fuel gauge sender. I should have gone that route to begin with, because it really only adds about 250 or so to the install.

Overall, I really like the Sniper set up, and there are a ton of options for down the road such as their Hyperspark stuff, etc. Scuttlebutt on the interwebs is that the Sniper set up is more reliable than other TBI units, but I have no experience to back that up.

Pictures without and with air cleaner assembly.

 

Taking off for example,from a red light was too sensitive like too much throttle since the Sniper throttle body linkage opens all four barrels evenly when you depress the throttle. Had a few backfires so I would have to lightly goose the pedal to avoid embarrassing moments with all four . After doing the progressive update it's more like a more of a modern car with constant smooth advance right from take off and when you drop the hammer the response is incredibly better.The progressive linkage that opens only the two primary barrels at first and then brings in the secondary barrels at a later point at about 40% into the throttle . If you're not having similar issues I would just leave it as is. I hear that progressive linkage and the software that comes with it is not for everyone tho. Thanks!!!

 

I did the holley sniper and hyper spark distributor combo. Did the progressive throttle upgrade too. Put the pump in the tank with a home made mount/ baffle. Used the factory steel feed and return fuel lines. It has been really nice. Allows everyday driver status despite heavy traffic where I drive. I did 0 tuning. It really does self learn ( except progressive throttle upgrade required changing settings )

 

I splurged and let go of the $9 for the linkage! What the heck - I tried it to see how it felt on my car. I wasn't having the issues you were experiencing. However I think I like the progressive linkage better. Its still learning so it may get even better. I agree it is more like a modern car feel - less like a dragster! But power is available! Thanks for the suggestion.

 

I did have to play with the system settings as to letting the system know when to start dumping the fuel on the second set of barrels!. I was having very mild hesitation when dropping the Boot. after adjusting it to just one percent it made a difference! ...Thanks!

 

I don't see 'dropping the boot' on the handheld. What do I look for?