355 TBI build help.

[old truck guy]

I am building a 355 for my 95 k2500. I was referred here from another forum for tuning help. I was planning on using Brian Harris but the general consensus seems to be beware. I am not a tuner and don't really want to be. I was told to come here and seek Dave or Mark but I'm open to anybody who can do the job.

On that note, here's what I have so far. I'm gonna use my L05 shortblock freshened up with a new set of h423dcp30's and a high pressure, standard volume oil pump. Its a 8600+ truck so its a 4-bolt, I haven't pulled the engine yet but I believe its a roller campatable block. I have a set of vortec 062's that I have blended the seats to the bowls, rounded the valve guide bosses off, minor porting and polishing on the exhaust side and spring upgrade for roller cam and higher lift. A little deck milling on the block for a nice tight squish and should be in the low 9's scr. My intake is a 2716 performer eps and I have a 46mm bored tb w/adaptor plate from tbiparts. My headers are flowtech 11508flt (1 1/2" primary) which I have modified with a custom set of 3/8" flanges made specifically for the vortec raised ports and a set of megs collectors which will be followed by a 2 1/4" mandrel bent dual exhaust. And the cam I have chosen is the comp xfi252 hr13 (08-464-8) 202/212 @ .050 and a 113 LSA. This cam is speced with 1.6 rockers but I was planning on using 1.5's because the .550 lift is pushing my lift capability of new springs and the vortecs stall out over .500 anyway.

How's this sound so far? I am speculating between 320 and 340 HP. I know my cam and exhaust are small but I want to keep my peak torque down low and have plenty of low to midrange power, not to concerned about peak power.

My tb came with 350 truck injectors. Are these gonna be enough for this build? I know I'll need a new fuel pump and higher FP. Need help with the particulars.

Thanks, Mike

[old truck guy]

As for the rest of the truck, it is a k2500 sclb, 8600+, 4l80e, 4.10 gears and 265 tires.

[devind]

I can tell you from experience YOU DO NOT WANT TO USE Brain Harris

However I am assuming since you had considered him and you said you really to do not want to do it yourself I am assuming you don't mind paying someone to help you??

If you are willing to learn how to use TunerPro to data log. Send davew of Old School EFI off of this forum a PM and he will be able to take care of your needs at a much more reasonable price then TBI Chips and it will work when he is done tuning it.

But again the key is you really must learn how to data log using TunerPro

[Roadknee]

Your block will be roller compatible. You might have to drill and tap some of holes, but it can be done.

I like your selection of parts with the exception of the intake manifold. I strongly encourage you to use an intake that can run heated water through the plenum. Otherwise, warm-up in cold weather takes a long time and it will be difficult getting the engine to run consistently as outdoor temp changes. GMPP has a vortec conversion manifold that is expensive, but works. Edelbrock has a perf rpm that can accommodate external plumbing of coolant through the plenum. Use one of these unless you're in an area where the temp never drops below about 40 degrees.

You'll want to purchase an emulator (Ostrich) from Moates.net. and get familiar with TunerproRT to facilitate tuning. This way your tuner can email you revisons that you can download to your ecm without the need to burn/mail/swap chips. It will save a lot of time in the long run. Your combination is pretty hot and will require enough tuning that I'd say the Ostrich is mandatory.

You'll probably want to run the AC Delco EP381 pump out of the 96+ vortec trucks. Keep in mind your truck and its wiring are getting old. I would install a new sending unit (Dorman or AC Delco, not Spectra) along with a hot-wire kit to ensure the power supply to the pump is adequate.

You'll receive differing opinions on injectors. Several have run the stock truck injectors with 22 psi with no issues. BLG355 has run 25 psi. 355chev has run 28 psi using a regulator spring from an EBAY supplier for several months and about 2,000 miles with no issues. His combination is very similar to yours and he's running 89% injector duty cycle at his 5,300 rpm shift point. You'll need at least this much fuel so either run 28 psi or a set of big block injectors at 16-18 psi.

Good luck. I'll be following this build with interest.

[old truck guy]

I can tell you from experience YOU DO NOT WANT TO USE Brain Harris

However I am assuming since you had considered him and you said you really to do not want to do it yourself I am assuming you don't mind paying someone to help you??

You you are willing to learn how to use TunerPro to data log. Send davew of Old School EFI off of this forum a PM and he will be able to take care of your needs at a much more reasonable price then TBI Chips and it will work when he is done tuning it.

But again the key is you really must learn how to data log using TunerPro

Absolutely willing to pay. My time is thin and by the time I buy everything to try it myself and learn it... Would rather pay someone who knows what they are doing.

[dave w]

Hi Mike,
I like your build plan.

Learning TunerPro RT is a good plan. TunerPro RT doubles as a scan tool also. I've yet to see or use an OBD1 scan tool that can provide as much information as TunerPro RT. Usually the cost of both ALDL cable and TunerPro RT (suggested $39 donation) are less than $100. Refurbished laptops vary in price, TunerPro RT works great on the low cost refurbished laptops.:thumbsup:

dave w

[1BadAction]

I'd find a set of the later model 17104288 BBC injectors, and run an adjustable regulator at 30psi to start (what the factory runs them at), then bump it up from there if necessary. Also, like these guys said, a heated manifold with the factory air cleaner/heat riser is the way to go. TBI being a speed density system calculates certain fuel dynamics and when you are injecting into a non-heated manifold, it changes that and makes a difference in running quality. I've had multiple TBI trucks that were used and f'd with before me, and they all run better after I install the factory air cleaner setup back on them.

[old truck guy]

I like your selection of parts with the exception of the intake manifold. I strongly encourage you to use an intake that can run heated water through the plenum. Otherwise, warm-up in cold weather takes a long time and it will be difficult getting the engine to run consistently as outdoor temp changes. GMPP has a vortec conversion manifold that is expensive, but works. Edelbrock has a perf rpm that can accommodate external plumbing of coolant through the plenum. Use one of these unless you're in an area where the temp never drops below about 40 degrees.

I have read about this but didn't realize it was as big of an issue. Is it still a factor after the engine reaches operating temp? It seems odd that the vast majority of aftermarket manifolds don't have provisions for this and if all of them, the one that does is the rpm which is more performance based where you would want the cooler intake charge. I chose the eps because it was the middle of the road as far as dual planes. How is the gmpp intake on a performance level? I don't think I want to use the rpm. With its larger intake runners I don't think it matches my build and would hurt low end. What about the 3704? I know its not vortec but would there be enough meat in the top of the ports to port match it to the vortec heads. I'm sure I could modify the mounting holes and I like how everything is in its stock location.

I guess part of my decision from here depends on egr. I had originally planned to delete it as I live in Ohio and don't have to get emmision check. Looking for input, pro's and con's.

[dave w]

I live in a mild climate (near Portland Oregon), so no issues using an intake without heated water through the plenum. On the few times I've been in sub-zero weather (usually trips up to Mount Hood OR in the winter) I have not experienced any cold start / warm up problems. I'm thinking if I lived on Mount Hood (6,000 above sea level) it would be a good idea to use an intake with heated water through the plenum, because sub-zero temperatures are very common during winter.

I Do Not recommend using the 3704, no real advantages to using a 3704.

To date, the best performance 355 SBC / TBI / Vortec Heads I've tuned used the GMPP TBI Vortec intake without an EGR. The engine is using a '7427 PCM, passes Washington State emissions (tail pipe testing only) with dual catalytic converters and dyno'ed 330 HP @ rear wheels. The GMPP intake throttle bores were modified to 52mm to accommodate using a 670 CFM 454 Throttle Body. The engine uses "Cop Car" 65 lb injectors @ 18 psi.

dave w

[old truck guy]

Any advantages to keeping egr? Anybody?

[1BadAction]

Any advantages to keeping egr? Anybody?
Emissions, MAYBE.

I tried to use mine as intended over a couple long stretches of highway between Dallas and South Florida, with a lot of datalogging and tweaking EGR tables. Never could squeeze any more MPG out of it.

[old truck guy]

Well from what I've been reading lately the myth of gaining performance deleting egr is just that, a myth. If they don't open at idle, wot or under heavy loads, then no effect on power and supposedly help run cooler and better economy during cruising. Unless anybody else has some input good or bad, I'll probably just leave it.

I think I'm going to go ahead and switch up to the gmpp intake if I can manage to sell mine. Put it and my adapter plate on eBay last night.

[1BadAction]

Well from what I've been reading lately the myth of gaining performance deleting egr is just that, a myth. If they don't open at idle, wot or under heavy loads, then no effect on power and supposedly help run cooler and better economy during cruising. Unless anybody else has some input good or bad, I'll probably just leave it.

I think I'm going to go ahead and switch up to the gmpp intake if I can manage to sell mine. Put it and my adapter plate on eBay last night.

Correct, you don't lose power with an EGR, I didn't say that. However, in my trucks case I didn't gain either economy or cooler combustion using it.

For me, the only benefit of an EGR (emissions) is not worth the carbon and soot they deposit inside the intake, especially when my truck easily passed dyno emissions testing without it turned on. :happy:

[Fast355]

Correct, you don't lose power with an EGR, I didn't say that. However, in my trucks case I didn't gain either economy or cooler combustion using it.

For me, the only benefit of an EGR (emissions) is not worth the carbon and soot they deposit inside the intake, especially when my truck easily passed dyno emissions testing without it turned on. :happy:

I got better mileage with the EGR turned off in the 350 Vortec Express. When I put the marine intake on it, I deleted the EGR.

I used a Victor Jr under a TBI and LOVED the way it ran.

[old truck guy]

Hello fast, thanks for the referral. These guys are awesome!

[old truck guy]

Continuing purchasing parts. Looking for input on rocker arms. Was originally planning on gmpp 12495490 1.5 stamped but I've heard they can be really inconsistent with ratio and while I've read some places that they are long slot, I can't find anything to support this. Don't know if they're capable of my .520 lift. Also considering crane 10800c and comp 1417-16. Looking for opinions.

[old truck guy]

Also has anybody used the crusader marine intake? Looks pretty identical to the gmpp intake without the egr provisions and its cheaper.

[Roadknee]

Continuing purchasing parts. Looking for input on rocker arms. Was originally planning on gmpp 12495490 1.5 stamped but I've heard they can be really inconsistent with ratio and while I've read some places that they are long slot, I can't find anything to support this. Don't know if they're capable of my .520 lift. Also considering crane 10800c and comp 1417-16. Looking for opinions.

That XFI cam you've selected has very aggressive lobes. I think you really should run rockers with the roller fulcrum together with some min 0.080" wall pushrods.

[Roadknee]

Also has anybody used the crusader marine intake? Looks pretty identical to the gmpp intake without the egr provisions and its cheaper.

I've looked at that intake and think it would work well. Take a close look at the throttle body mounting pad. The throttle bores look closer together than a 2bbl TBI. You might be able to re-drill the flange and offset-grind the bores or just find an appropriate adapter plate.

[BLG355]

Continuing purchasing parts. Looking for input on rocker arms. Was originally planning on gmpp 12495490 1.5 stamped but I've heard they can be really inconsistent with ratio and while I've read some places that they are long slot, I can't find anything to support this. Don't know if they're capable of my .520 lift. Also considering crane 10800c and comp 1417-16. Looking for opinions.

I'm not sure if others have had too many issues with this, but with my 95 K1500, I tried full rollers at first, and they were noisy and giving me excessive knock counts, On a ten minute run I could get upwards of 10,000. I switched to comp cams magnum roller tip rockers and the only knock counts I get now are during initial startup, they other day I ran a 18 minute log and it have 246 knock counts, which is what it had during startup.

From what I understand there are ways around it and you can change things in the tune to reduce them or change for an LT4 sensor or something, but I just wanted it to be able to run without issues and I'm a new tuner so I changed them out and had no more issues.

http://www.jegs.com/i/COMP-Cams/249/1418-16/10002/-1?parentProductId=

This is what I have on right now, they are more money than the regular stamped rockers, but they are good for higher spring pressures and lift, plus are very tough. I used the 1.6 ratio on my Isky 252/257 Hyd Roller cam to get just under .500" lift. The only issue with them is that they are thicker than cheap rockers, so you will need a very thin socket to turn the lock nuts because of this. If you don't have them already, good screw in studs will almost me a must, like ARP.

BLG

[old truck guy]

I went with comps rpm1417-16 magnum roller tip rockers and magnum 1 pc hardened .080 pushrods. These are comps recommended items for my cam. I already have a new set of gmpp 12371042 roller lifter kit. Are these lifters gonna hold up to the aggressive lobes of my cam?

[Roadknee]

Yep, those are good lifters.

[old truck guy]

Ok been away for a few months but still making progress. I got my heads back from the machine shop and the port and polish, fresh mill and new springs look awesome. Gonna throw in a set of screw in studs just for a little added insurance. Sold the Edelbrock and bought the crusader marine intake. Bored it to match the 46mm throttle body and I also machined in a boss on the front, right corner of the plenum so I can utilize the stock vacuum brake booster line.

Converted my fpr to adjustable one by removing the stock set screw, retaping the hole to 10-24 and installing a 3/4" long allen head cap screw with a jamb nut. Drilled a 1/4" hole in the base below the fpr between the fuel line bosses. The head of the cap screw fits snuggly in this hole and I'm pretty confident that I'll be able to adjust it on the vehicle. Also I finally found a 92 caprice cop car in a junk yard a couple hours away. I made the journey and thankfully it had the 68lb injectors in it. Sent them to Mr injector and had them cleaned and flow tested and im good to go :-). I'm hoping to get by with 15psi fp because i just replaced the pump with a new ac delco less than a year ago lol but if not I'll be buying a new fuel pump and spring. Guess will find out when I fire it up and do some data logging.

Have pretty much all my parts and hopefully will be pulling the motor in the next couple weeks to get the short block done. Have laptop and will be downloading tuner pro rt. Mark w is going to do my initial tune but I will need to be able to do data logging and I guess make final revisions. What all do I need to get?

Thx, Mike

[old truck guy]

Bump

[PJG1173]

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?3256-Tuner-Pro-FAQ-and-Tutorials under hardware should get you started

[old truck guy]

May be a dumb question but I don't know. Do both injectors fire at the same time or is one for 1, 4, 6 and 7 and the other 2, 3, 5 and 8? I've noticed that different intake manifolds vary on which side feeds what.

[brian617]

TBI injectors each fire every other DRP.

https://web.archive.org/web/20030216033345/http://www.fortunecity.com/rivendell/oddworld/24/ECM/alt_tbi.jpg

[old truck guy]

TBI injectors each fire every other DRP.

https://web.archive.org/web/20030216033345/http://www.fortunecity.com/rivendell/oddworld/24/ECM/alt_tbi.jpg

So there is a specific injector (wire harness) for each of the two groups of cylinders then? I suppose all I have to do is look at a stock manifold to see which injector harness feeds which group of cylinders. Are they polarity sensitive?

[PJG1173]

you have inj A (two wires) and inj B (two wires). one wire form each injector goes to fused power and the other wire goes to the computer on its own pin. each injector fires every other distributor ref pulse. they are not dedicated to any particular set of cylinders. the computer does not know which is feeding which cylinder. or even which cylinder is in what position. it is very basic injection.

[old truck guy]

you have inj A (two wires) and inj B (two wires). one wire form each injector goes to fused power and the other wire goes to the computer on its own pin. each injector fires every other distributor ref pulse. they are not dedicated to any particular set of cylinders. the computer does not know which is feeding which cylinder. or even which cylinder is in what position. it is very basic injection.

I agree that the computer doesn't know which cylinder when but it's clearly a mechanical relationship. If you look at how an intake manifold is divided, one injector supplies cylinders 1, 4, 6 and 7. Firing order being 18436572, those cylinders are all 180 deg apart. The other injector cylinders 8, 3, 5 and 2, also 180 degrees apart from each other and 90 degrees apart from the other group. As #1 begans the combustion stroke, #6 is begining the intake stroke so it makes sense to me that you would want the injector that feeds #6 to be firing on the #1 spark pulse, every thing else falls naturally into succeeding order. If the wrong injector was firing, everything would be 90 degrees off of the corresponding intake stroke.

Now back to my previous question. I understand that there are two wires to each injector. My question was are the injectors polarity sensitive?

[dave w]

Now back to my previous question. I understand that there are two wires to each injector. My question was are the injectors polarity sensitive? No. I like to be consistent, I wire both TBI injectors the same.

dave w

[old truck guy]

Well it's finally time. Engine coming out this week to get the short block done, ordered tuner pro rt and everything from moates. Everything else ready and waiting to bolt onto short block. Dave w is helping me with tune and creating my startup chip. Is there anything I can be doing in the meantime to learn tuner pro and data logging? Unfortunately I don't own any other OBD1 vehicles.

[Roadknee]

Download the xdf for your ECM mask Id from this site and start studying the various parameters and parameter comments. You can spend hours learning what you can modify in the tune.