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.

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.

[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.

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!