Soupyman

I plan on doing an engine swap and I am converting a carb 350 to a hopefully sniper efi or something similar. If I do this swap and put it into my 89 Iroc Z what exactly do I need to change on my car to make work good in my car. I'm thinking to chip the car to work with the new injection system on it but do I need to do the fuel system change that is in the kit or a new distributor.

anesthes

iTrader: (12)

Your 89 was already converted to carb?

It would be helpful to know more about what they did to your car. In theory, if your electronic fuel pump is still in place you can wire the sniper harness to control the fuel pump, plumb it in, and then you can lock out the HEI electronic distributor and use the sniper to perform ignition control as well.

-- Joe

midias

Do an in tank pump and skip their fuel system. You can use a regulator vacuum advance mechanical distributor until you want to change it out

anesthes

iTrader: (12)

Are you thinking of Fitech? or does Sniper also sell a bizarre external fuel system now too? That silly external reserve tank and pump system always freaked me out.

For most of the retrofits I've seen, Holley has in tank fuel modules under the Sniper line for fuel tanks that originally don't have OE style fuel pumps available. (i.e, my 68 corvette). But for a thirdgen, I agree 100%, use the OE fuel sender with pump (or better yet upgrade to a plastic LS tank like I did on my thirdgen).

-- Joe

midias

. The standard sniper setup has an external pump mounted under the car. They are louder and less relible than an in tank version holly makes a retro tank for most muscle car applications but for our cars a factory pick up and pump or maybe walboro255 is the way to go

anesthes

iTrader: (12)

Gotcha. Yeah inline external pumps are loud and overheat.

-- Joe

Soupyman

it wasn't converted to carb everything but the suspension a and transmission is factory

midias

There is no factory carbed 350 thirdgen

Soupyman

the 350 I plan to swap in to it is from 67-72 quadrajet. I want to swap that to a sniper efi system and then swap it into my 89 camaro. I basically just wanted to know about the fuel system and what to do for it. Other than what you guys said I was thinking of swapping to a new fuel tank and putting the parts from the kit but to your guys recommendations it's not a good idea. This also may happen a few years from now as I need to save more money for other parts and another car as this is my current daily

midias

Don't bother with that block get a modern roller block

Soupyman

can you elaborate on that. Literally everywhere person I've talked to about it said it's a good motor especially since it's a 4 bolt main so I should if possible turn it to a 383. I don't have the funds to make a new block work unless I find a cheap enough long block that'd be easy to work into the car.

Komet

There have been a lot of issues with flat tappet lifters in modern times. You can retrofit the 4 bolt main block with a roller setup which should improve your odds of not experiencing catastrophic valvetrain failure, but the cost might be more than a junkyard l31. Just depends on what deals you can find.

midias

If you're going to use that block you better take it to a machine shop and have everything checked out but because all of those blocks were designed for flat tappet cams they're not really worth the effort or the money. You want a modern roller block.

Soupyman

ok I double checked the engine and did more research on it, it's a 3970010 350 4 bolt main. Does this make any difference at all because other forums where saying it's a common and pretty good motor. Someone even said to keep as many as you can but others said it wasn't great. I do plan to send it to a machine shop as it sat outside for a while and I don't know how bad it is internally because ran when taken out could mean anything and I want my peace of mind when I put it in

anesthes

iTrader: (12)

That was one of the most mass produced blocks GM ever cast. Was available in various stroke configurations, high horsepower, low, 2 bolt, 4 bolt, etc.

As others pointed out, it's more expensive to run a retrofit roller cam + lifters in an older block than it is to use a OE roller block. There are plenty of 4 bolt main roller blocks out of 1 ton trucks and other things available.

By the way, I have a 3970010 engine out of a 1974 Chevelle, 145 horsepower..

-- Joe

Soupyman

so basically it's not worth modifying this engine and I should go with another motor?

midias

The block its self is probably fine after some clean up but you really want a roller cam. I have an 010 + .030 4 bolt block in my firebird and run a flat tappet. Roller is much smoother but thats the way my car came when I bought it unfortunately I will have to spend 1-1400 some day to convert it or get another block

Soupyman

ok so itll take some more work and after i clean up the engine i should switch it to a roller cam and change heads is what im gathering from this and it would make this motor worth using

midias

If a machine shop says it's good then it is. Convert to roller cam, toss the factory to heads, rebuild the bottom end and go.

anesthes

iTrader: (12)

A non-roller block ends up costing you more in the end. Retrofit cams are slightly more expensive, retrofit rollers are significantly more expensive, and you need something to retain the cam, which I've found aluminum cloyes timing covers (again expensive) work best.

For a factory roller block, I've been using LS lifters (about $120 a set) with good success. OE style roller cams are cheap. I personally wouldn't put the money into redoing a 010 non-roller block. Just not worth it.

-- Joe

Clemson327

iTrader: (4)

I’ll be doing something similar on my carb’d 383 soon. I’m installing the MSD Atomic 2 system (basically a Sniper with a different design) along with a Walbro external fuel pump (GSL392) which is supposed to be quieter than the pump supplied with the Holley kit. I’m using a Corvette filter/regulator by the tank to keep the return path short and will use the stock 3/8 steel line to supply fuel to the engine bay.

Kingtal0n

FYI

Modern 4.8/5.3/6.0L Engine 2002-2007 from Silverado, Denali, Tahoe, Escalade, etc....
Will handle 600 to 1000 horsepower on all factory internals

Example:
I got an LM7 for free from a junkyard that had over 10 of them, they gave me their worst looking one with unknown mileage.
The LM7 is an Iron 5.3L Capable of lets say 820BHP (roughly 700rwhp) in a daily driver config
Installed in 2017, I already put 43,000 miles on it at 600rwhp, drive it everyday just change the oil
It was just supposed to be a test engine (I wanted the aluminum block) since it was my first LS ever I was worried I would damage it but now that I've seen what I need to see I don't have the heart to remove a perfectly good engine so the mileage just keeps going up while I prep a aluminum 5.3 on the side for whenever.


Other example:
I recently tuned an L33, 2007 Aluminum 5.3L From a silverado with 140,000 miles, to 800rwhp
It weighs 120lbs less than the LM7 and supports +200bhp extra horsepower due to Gen4 style rods
The cost is higher (It wasn't FREE) But still less than you will spend for anything else at that level of output

I know it is alot of work to retrofit one of those engines into some thing older but the payout is that you never need to buy expensive engines again for just 1000 horsepower or less.

They also benefit from modern SEQ-EFI electronics, the factory computer is more powerful than any stand-alone and has features such as torque management which are desirable to preserve drivetrain life and enables high mileage even with a powerful automatic transmission build such as 4l80e which is what I used and rebuilt for street strip specifically. The factory computer is around $45 to $60 from most junkyards and provides all the necessary features and functions for up to roughly 1000rwhp and max fuel economy potential, as it can be programmed just like a stand-alone for injector latency and phase.

So you save thousands on the engine, and thousands on the EFI setup. There are still many expenses to consider but at least you saved thousands and eliminated costly repairs and service issues. For example if your stand-alone computer fails or shorts out or gets wet etc... you lost thousands but the OEM computer is like $50 all day and water proof. Same thing with the engine, one day it rains hard and hydrolocks or whatever (not your fault **** happens) and so you get another complete engine for $1200 or $500 or whatever. Just have one standing by its so affordable to carry extras nearby.

If the goal is simply to have a reliable vehicle you can assure those are among the most reliable V8 engines ever produced (all 02-07 trucks can reach 300,000 miles or whatever easily) and also the cheapest and highest availability. They won't make big power without forced induction but it can still service as a reliable daily driver. But I wouldn't bother without the turbo. gg

efiguy

iTrader: (2)

Thats a general statement and simply not true. I’ve had a Mallory external pump on my car for over 15 years. It’s quiet and still working.

anesthes

iTrader: (12)

How many OEM vehicles have inline fuel pumps?

-- Joe

midias

Ok here is the more accurate statement. Intank pumps benefit from cooling from the surrounding gas which leads to extended life and have less noticeable noise thanks to the tank surrounding the pump and deadening the sound

efiguy

iTrader: (2)

I agree. Joe twists and argues everything I say for some reason. One of the many reasons why I’m not on here much anymore.
Thanks.

anesthes

iTrader: (12)

You came into this thread to respond to my comment.

​​​​​You joined the forum to market your services and resell EFI components, yet never registered as a paying vendor. Feel free to move on at any time.

-- Joe

efiguy

iTrader: (2)

I’ve offered a ton of help for free over the years, but you’ve chosen to overlook that. That’s fine, it is what it is.

Kingtal0n

External pumps are the worst fuel pump you can possibly be forced to use. Nobody should ever need to subject their fuel system to an external pump, given the existence of in-tank fuel pumps and purity/quality for modern fluids applications. Absolutely pure fuel is desirable. Ideally fuel and oil pumping device will be submersed in this absolutely pure fuel or oil substance and able to impart energy to the fuel/oil in the form of pressure and kinetic energy, forcing it through lines/crevices to the engine fuel rail/oiling galleys where injectors/orifices allow fractions of this pure fuel/oil and allow the fuel to wash inside your rotating mechanical metal precision parts which must be submersed in protective layers of pure engine oil and avoid mixing the two. Their purity and separation is part of what allows the engine to achieve high reliability and minimum wear and part of optimizing these systems is submersing their respective pumps to near the main reservoir or estuary.

Joe was doing you a favor, he gave you the best possible advice he could think of. Absolutely 100% experienced knowledgeable information for your success

OEM EFI should NEVER use external pumps because from an engineering point of view:
1. It is difficult to keep clean. The pump and wires are more difficult to ensure cleanliness and security and must carry high current. Insulation protects but also retains heat. The whole apparatus is a filth attracting structure that contains an absolutely pure liquid. During service a much higher likelihood of systemwide contamination exists.
2. It is difficult to cool properly. The pump itself being external has nothing but air cooling, so the pump must be mounted in a place with great airflow or limited in current draw which will reduce flow. The type of vehicle matters because more power = more fuel flow = more heat.
3. Its not pretty and its more exposed to road debris. There is a good chance with good airflow the pump will be easily visible or the location unsuitable due to road debris concern. The power of the pump and it's heat dissipation rate must be compared with the least possible airflow condition and the results are not good enough for OEM reliability where the mounting location of the pump is receiving poor airflow and the pump itself might be up to 8 or 11amps which can generate significant amount of heat energy. High temperature is a big problem for electrical fuel pumps so this is red flag to the engineer, calculating power and heat dissipation in a 11amp electrical device crammed under the rear seat cushion area hidden by plastic panels to try and keep it from getting hit by road debris. How DO you give something great passive airflow while also keeping nearby kicked up dirt from reaching it? The vent & cooling system costs more than the pump if you do that right. (Just put it in the tank, he said)
4. It is difficult to control the noise and vibration. The issue of pump vibrations and pump noise. Vibration is unwanted in both internal and external pumps. External pumps are more difficult to control and more difficult to mount in a vibration resistant manner due to their more bulky, protective, utility style external appearance and lack of supportive surrounding features such as rigid fuel container like a fuel tank. To make an external pump capable of keeping it's insides clean or helping with vibrations means using many types of layers of protective sheaths and external dampers and this makes a pump more bulky, heavier, difficult to cool.
5. It might not prime. The external pump often depends on some kind of gravity or feature priming system which further decreases reliability in a daily driver application, an internal submersible pump has no such dependency. The influence of gravity, although somewhat dependable, is not something an engineer should gamble with. It may have unintended long term consequences or unexpected results after some time has passed by which point its too late, you've got to give everybody new fuel pumps or new cars or something. Best to eliminate those type of variables and mounting the pump inside the tank is a easy way to eliminate something weird happening down the road with a gravity reliant system which was supposed to ensure the external pump would always prime properly. KISS

efiguy

iTrader: (2)

All good points. I never argued the attributes of an in-tank pump did I? No, all I said was mine works fine and has for 15 years. And of course I get attacked for just offering my own first hand experience. Hence the reason why I’m not on here much anymore. Done here. Thank you.

Kingtal0n

You kinda swung first. Your message was not very friendly. You could have been more polite. But I am rarely as polite as needed myself, so I do not hold or fault you for that one bit. Actually it is preferable if all the males fight each other and establish dominance on the internet. Right? Its so important to testosterone production I bet. At least it keeps males from pressing "like" on each other, so cringe those types. I'd rather not be liked, thank you

Seriously though you are getting way bent out of shape out of something so small. Joe did what advanced heuristics does to super-experienced individuals, he gave the shortest most powerfully applicative directions and advice possible, a small sentence which contains all the knowledge but without much explanation (you'll have to trust him). If a doctor says 'Eightyfive percent of all cholesterol is manufactured by the body and blood protein that cells need to live is mostly albumin' do you trust him and infer from that information that Eggs are the best possible food you can put into your body? Or do you come online and tell him 'hey I never ate any eggs and I'm fine!!!' Joe is like a doctor trying to improve your life with a short sentence. you'll never miss what you never had

efiguy

iTrader: (2)

As mentioned.

Kingtal0n

I'm a little concerned and confused by this behavior. When I'm done, I just leave. I don't tell people that I'm leaving, I don't look back to see if they respond or whatever is written. You must push these from your mind to detach yourself completely. The fact you keep coming back is... interesting. I don't quite understand what you are really doing, or what you think is happening, but you aren't done if you keep reading and checking and responding thats for sure. lol