This is for my truck which is off-road use only. It is trailered EVERYWHERE it goes, it never ever drives on the road. It is a basic 1984 Chevy K10 shortbox, weighs about 5,500 lbs IIRC. It has a granny gear 4 speed with a 6.55:1 first gear, an NP 205, Dana 60 front axle and 14 bolt rear, both with Superior Axles, with 4.10 gears. It has lockers in both ends, beadlocks, and 39.5" Super Swampers (TSLs in front and Boggers in the rear).

I drive this truck on some of the most extreme trails in North America. It ABSOLUTELY MUST IDLE! I can handle a little bit of chop because I have such a low first gear (and I intend to have even lower gears one day) but I can't have something that I'm fighting to control. Dragster idle, while it sounds cool, is not acceptable in this application. That said, I want strong midrange power and I'd prefer an engine that can rev to 5,500 RPM. I know it sounds like I want it all, but if I can't make significantly more midrange power than the stock engines I've been running for years, I see no need to build an engine.

Right now it has a nasty rod knock and it's time for me to upgrade the engine. TBI has been planned for several years as I have a donor truck and now is the time to act. I DO want more power but I do not want to throw away my dream of having a fuel injected truck to go off-road with, so the engine must work with TBI.

I want to build this engine on a reasonable budget. I'm not going to set dollar figures right off the bat, but if it can be done for $2500 or less, I will be pleased.

Here's my idea thus far:

1987 350 block, 4 bolt main from a C30

Bore if necessary, hone with torque plate, line hone, deck to zero for proper quench with composite head gaskets

383 kit with flat top pistons, probably hypereutectics, nothing really special needed here.

I can then use larger chamber heads to keep the compression reasonable, so as to not **** off the fuel injection system. I don't care if this thing will only run on premium fuel as I put maybe a dozen tanks of fuel per year through it. If having an engine that will only run on premium gains me power, however slight, I'm all for it. This truck isn't for road use anyway, so max power is the goal (within the other guidelines)

CAM? I'm scratching my head here. This one looks real good,

Camshaft Specifications

Comp suggested a smaller one, I may go that route as well.


That said, more motor needs more cam, so I'll let y'all decide, or if you have another suggestion, I'm all for it. These two cams have 114* LSA, which seems on the surface to be EFI friendly.

Heads...here's where I'm really scratching my head. The Vortecs look great, but of course you need several special items to make them work so the price isn't always the best value. They're also small chamber so I'll need a dished piston to use them. It is possible to use a set of aftermarket heads that will accept a stock TBI intake, which will save money, but isn't the stock TBI intake very restrictive? I don't want to choke my engine. Let's just say heads are up in the air. S/R Torquers? Darts? Should I consider aluminum heads given the environment that this truck is going to run? (Sand, rocks, mud, water, you name it, and it might get damn hot doing it)

My truck already has 1 1/2" primary headers and dual exhaust. I will be installing an O2 bung to use the TBI.

I'm open to opinions 100%. I want to do this right. I've put it off for 5 years by using used engines, and I'm tired of replacing engines. I want one that is going to serve me for a long time.

I'd like to also say that I've been a long time lurker, and I'm glad I finally made a post.

 

Nobody here has built a stroker?

 

"This is for my truck" This is a 3rd gen Camaro and Firebird forum.

 

altho he said it was for his truck, its the motor which is gonna be TBI that is the issue at hand, its like u puttin a 350tbi into ur daily driven maro/bird.

if this is a budget build go for a LT1 cam with 1.6 rockers, and ported L98 heads and a good tune should give u what u want/need. also those headers are gonna be 2 small so i would upgrade to 1 3/4 primarys and prob dual 2.5" exhuast. also the Edlebrock Performer TBI would be a good choice. u will need to upgrade ur fuel pup(prob to a TPI that should work) and the injectors. also since u said its gonna be off-roaded, have a fuel kill put in when low oil pressure is present that way u dont destroy the motor, also a rev limiter wouldnt hurt just in case

 

(drags out soap box) YOU'LL NEED TO TUNE IT ( puts away soap box)

Your going to **** off the the FI with any mods that add power, so your best bet is to be friends with the FI so you can make all the power in the world and have your cake too. A high compression 383 will have mid range grunt that will yank your head off, providing you go with a mild cam like a LT1 cam. If you don't want to learn to burn your own chips then either put a bone stock 350 in it or stick with a carb. Your idle is usually the first thing to go screwy when you start modding TBI'd engines, tuning will bring this right back into line.

If I had to pull out the old air dyno I would say that a 9.5 to 1 383 with a LT1 cam and vortec heads would make around 300 hp and 450 maybe 475 ft/lb of torque. It would idle dead smooth at 500 rpm, start anytime and have a crack that would wake the dead. Think of that 450 ft/lb of torque through your tranny and rear end would make 11,309 ft/lb of torque at the axle, thats 6,784 lb. of thrust at the tire. You could litterally climb a tree with that much torque, and this isn't even considering any gear reduction if you put it in low range. This motor would rev clear to 6 grand with no problem, but it's sweet spot would be more like idle to 4500.

 

This site is widely regarded all over the internet as THE PLACE for EFI questions.

On that note, I guess nobody has ever built a street 383 for TBI then...because an idle-5000 or so powerband is exactly what one would want.

83-Ta-5 speed
I hate to tell you this, but 1 3/4" long tubes have no place on any truck engine. They would absolutely kill my torque for very little top end gain. 1 5/8 *might* be better than my 1 1/2" on this stroker, but probably not enough to warrant changing.

I'm checking out the LT1 cam, which appears to be a roller cam. Truck engines weren't roller until 1996, so I don't think that's going to be an option. I am going to try to see what the parts cost, though, as my 1987 truck block will be, "Roller ready." I'd need a new set of roller lifters though, obviously, which are pretty expensive!

I'm actually more concerned with what TBI can handle. What is the limit? Where do I stop? I don't want to spend $3k on a motor and find out it won't run well with TBI.

I definitely am going to try to burn my own chip. I just want to make sure I don't build something that is entirely incapable of running on TBI.

Thanks so much you guys.

Oh and the 11,309 lb feet of torque at the axle sounds very good. I have a 10.5" 14 bolt with Superior Evolution Series chromoly axle shafts, so I'm sure that it will be just fine with some neck snapping torque.

If you guys have the spec on the LT1 cam so I can plug it into DD2000, I'd appreciate it.

 

[QUOTE=Downzero] I'm actually more concerned with what TBI can handle. What is the limit?

Holley suggests theit 670 cfm series supports 275 HP which is comperable to our 7.4L GM unit and their 4 barrel units(600-700-900 cfm) will support up to 600 HP. my (2) 80 lb inj's @19 lbs FP flow 96 lb / hour and support 340HP @80 duty cycle.

 

[quote=Ronny]Support for 340 HP sounds like exactly what I'm looking for.

I guess I'll just build this thing and figure out what it takes to make it run optimally later.

I'm thinking I'm going to build it with World Products S/R torquer heads, my Edelbrock Performer intake and an adapter for the TBI, 9.5:1 compression, Comp Cams 12-256-4 cam, and run from there.

DD2000 calls that 425 ft lbs @ 2000 RPM, 302 HP @ 4500 RPM and it'll pull through at least 5000 although power is dropping off a wee bit.

Sounds like a recipe for stump pulling to me.



This is my truck BTW. If you read Fourwheeler Magazine you might have seen it in there a few years ago. It's got a few more dents in it now than it did then, as you can see from the pictures.

 

I beg to differ, I ran 1 7/8" primaries, 3.5" collectors, and Dual 3" exhaust with a X-pipe on my 305. I picked up torque from just off-idle, all the way up. RWHP gains were obvious from 2,000 RPM and up, and this is a 305! Gains from 5,000-6,500 were incredible. I also know for a fact that the peak % TPS reading to pull this certain hill in OD with the cruise set on my way to work decreased by nearly 8% (42% down to 36% on a consistent basis, cruise RPM is roughly 1,500 @ 55 MPH) Excellent setup for my 5,500 lbs VAN. The 1 5/8" primary Flowtech 11500s were JUNK compared to the replacements

Some trucks were roller, it is hit and miss though. Usually the block has roller provisions although often times untapped. A roller cam is the way to go though. You can get good HP from a flat-tappet, but the roller with the same specs will make more low to mid-range torque, more idle vacuum, idle smoother, have better throttle response, while getting a little more HP.

I have yet to find the limit. 301 RWHP @ 6,500 with a 305 and was not short of fuel or air.

I will get back with the specs, I have seat to seat specs for a F-body LT1 cam which will be more accurate for DD2000.

PS- I have run 68# injectors at 35 PSI with a VAFPR to get 22 PSI at idle, worked well.

 

No truck had a roller cam until 1996 when the Vortec engines came out. The 86-95 truck blocks ARE roller ready, as you say though.

I'd be very interested to see dyno sheets from your 305 showing a 1 7/8" header being superior in low RPM torque over 1 5/8", but I'm not changing my headers either way so it doesn't matter. Headers will break my budget.

Either way I'd prefer we stick to the topic at hand. As it stands right now, I'm ready to build this motor and I will be dropping it off at the machine shop next week.

 

I beg to differ again, some DID. I pulled apart a stock, untouched 1992 G20 Van TBI 350 (uncle bought it new in 1992, gave it to me with 265,000 miles when the 700r4 died and it was not worth him fixing) that was roller. I pulled the stock roller cam out (peanut 305) and put in an early F-body LT1 roller, using the stock lifters, pushrods, etc, with a good set of valvesprings. It was definately not a Caprice engine as many have suggested. It had 4 bolt mains, 193s, sligthly dished pistons, 5 quart oil pan, GM high volume oil pump with 70 PSI spring (80 psi oil pressure gauge).

i understand, but was just pointing out that it is not set in stone that 1 1/2" will work better. It really depends on the combo and how it is setup.

I would have to dig them out, buy a scanner, scan them, and post them. I am lacking a scanner at this time so it is not possible.

I honestly don't see where we got off-topic. You asked how to get the most power out of your TBI and we told you. Then you said we were wrong.

The early LT1 roller cam(the one that I put in mine) has the following specs

273/279 @ .006", .447/.459, 115 LSA, 112 ICL

 

IMO, as far as cams go, modest duration with an aggressive, high lift profile and good flowing heads that dont have excessivly large runners CC wise should be a good recipie for lots of low to mid-range torque and power. You could also probably get away with a tighter LSA if there isnt alot of advertized duration. Youd obviously have to convert over to a roller with retrofit roller lifters (wouldnt use the stock spider assy.).

As for the heads, I wouldnt drop the compression real low, just keep it reasonable so you dont get into high load detonation. Once youve selected your heads, give Comp a call, tell them what your looking for, and get a recommendation for a cam. I wouldnt tell them you'll be using TBI, just tell them that you dont want alot of overlap.

 

I am building a motor. I really don't care what you think about my choice of headers, nor do I care about your Uncle's van.

I started this thread to be sure that I was building something TBI capable. That answer is yes.

I shall start my next thread in the PROM burning area when I get to tuning.

Thanks everyone, including fast355, for your help. It is much appreciated.

 

It sounds like you have a good plan so far. Hope it turns out well.

Your headers will get you around just fine, not debating that, just from the power stand-point they could be bigger. You do want 5,500 RPM power potential from a 383 or so you say. Someday you may want to step up if power is the goal is all I was saying. Please don't read this as me arguing with you, I am not, and I know what it is like to be on a budget.

Tossing the roller cam application out there was just to say that not all trucks are roller-less. There are TBI trucks that came from GM with roller cams. I have seen many over the years doing intake gaskets, timing chains, etc.

Have you had the intake off your 350 to see what is in there? Determining what is there would be a great start. It will give us an idea on what you can use for a cam and stay within the budget.

Will be glad to help when you reach that point.

Attached is the DD2000 dyno graph I get from the following combo

9.5:1 383
Stock L31 Vortec heads
Stock F-Body LT1 roller cam
Stock 400 CFM @ 1.5 in/hg TBI unit
490 CFM Ultimate TBI moded TBI would give 12 HP/8 ft/lbs @ peaks
Small Headers with Good flowing exhaust
HP=354 @ 5,000 and TQ=429 @ 3,500
It will make power to 5,500, but its real sweet spot would be from off-idle to 4,700.

 

The 350 I'm using is an 86 block with a flat tappet cam. I'm not using the heads.

 

The 86 block won't have the roller provisions, so forget about the LT1 cam without extensive re-work using retrofit lifters, timing button, etc. Good choice on not using the 86 heads, they were terrible I am sure.

This sounds like a good fall-back plan. I don't know if I would use the SR Torquer heads though. Dart makes a much better pair of heads for only a little more $. You are looking at $200.00 more for the build to get a much better pair of heads. The Darts have cleaner, better shaped as cast ports, high swirl type fastburn chambers(very similar to the Vortecs), good springs, good hardware to keep them going for a long time.


JEGS High Performance - Dart SB-Chevy ''Iron Eagle'' Heads

 

Unless I score a used roller cam, there's pretty much no way to build a roller cam engine without breaking the budget.

 

Which is why I said to scratch the roller cam idea to stay within budget. You are better off with good heads and a weak cam, than a great cam and lame heads.

 

I've heard that DD2000 tends to exaggerate roller cam performance anyway, but I don't have any dyno numbers to prove it.

 

I seem to remember that too, but it is not nearly as bad with seat-to-seat duration. The numbers for my old 355 were right on with what it made. IIRC, DD2000 put its output at 340 HP and I made 279 RWHP on a Mustang Dyno.

 

I'm just so anxious to get this done. I wish my shop wasn't 100 miles away.

 

The big problem isnt the cam as much as its the lifters. Good retrofit rollers are $$$. Ive seen less expensive ones that wouldnt trash the budget, but Im not sure how good they are.

The next closest thing to a roler is the XE suggested by Comp. The one listed looks good for your 383. I dont think it would be too much on a larger displacement engine. It should also idle smooth with that cam. I wouldnt go with the 256, that may be too small for a 383. That would probably be like putting a '929 in a 350. I have a crappy flat tappet in my 350 with similar duration to the 256, and although its doing a good job of literally shearing the car in two, it starts falling off toward 5k.

Also try to get a 2" TBI. Holley sells them, but theyre kinda pricey at around $350. You can probably get one used for < $100

 

I don't need retrofit roller lifters....my block is roller-ready, but I would need a complete set--which aren't cheap.

 

I never thought much of the spider assy. that came from the factory. If you where using a mild cam like the LT1, then you could probably use the spider assembly with some good used roller lifters. As long as the rollers arnt scored, the needle bearings still operate smoothly, and theyre in reasonable shape, youd be good to go. For a high lift cam, the retrofit rollers would likely be better, but that doesnt sound like an option on your budget.

 

I haven't heard much good about retrofit roller cams in general.

 

Does anyone think that 9.9:1 is too much compression?

 

DP...

 

Sort of irrelevant, but you dont necessarily have to use a retro-fit roller, but the stock spider assy. may not work with a smaller base circle cam

As for DIY-Prom/tuning, I wouldnt bother using the stock computer Theres alot of fudge factor thrown into the programming to compensate for the fuel dynamics and the tables are really small. Basically it sucks and it was just and excercize in frustration for me. While there are other options, EBL (search over on the DIY-Prom board) would probably be your best bet for functionality and ease of use.

 

I figured I'd just bring my old thread up to the top so I could update you guys.

Update:

As of now, I've ordered RBob's EBL setup from DynamicEFI to tune this monster. I ordered the Burn1 from <u>DIY Fuel-Injection Tools:</u><br>Created by an EFI enthusiast for EFI enthusiasts like you! : Moates.Net as well as a ZIF socket and 27C512 chips.

My engine is out, I ended up sending the one out of my '87 R30 to the machine shop. It's getting line honed, bored .030", and decked to .005". An Eagle crank and Eagle SIR rods are being used for the bottom end, and Keith Black -18cc pistons. This will net 9.52:1 compression with a Fel-Pro 1003 gasket. I am using Dart Iron Eagle heads with 64cc combustion chambers and 180 cc intake runners. I will be using my Edelbrock Performer intake with an adapter and a Comp Xtreme Fuel Injection cam, PN 12-365-4.

I installed a TPI fuel pump in my tank, an injector spacer, and an adjustable fuel pressure regulator from Turbo City. I'm using 61 lb/hr injectors, the stockers from my '87 R30 pickup. I'll be welding an O2 sensor bung in both header collectors, one for my regular narrow band for the ECM, and the other for the wide band that I intend on purchasing eventually.

As it stands right now, I plan on starting with 25 PSI of fuel pressure, setting my BPW constant lower proportionally and firing the engine, and then letting the EBL help me with the VE tables from there.

So far, one hell of a plan. I'm a bit nervous about making sure my TBI swap, new engine, and all these computer modifications work at the same time, but I'm sure I'll get there eventually. We swapped the entire wiring harness to include the fuse box and everything in the cab, and the speedo/dash so the install is 100% factory with no hacking up of the harness. It's a beautiful thing.

Thanks everyone for your help.

 

For initial startup, you can always use a 3-way regulator and a carb. You can set the timing tables up with a timing curve in the ECM similar to what youd use on a standard HEI dist. Odds are the engine probably wont really even run on the first startup with the TBI without being tuned so using a carb for the initial run would be a good idea untill you feel comfortable with everything else.

 

I don't have any carbs that I'd be willing to put on a $4000 engine. The TBI has to work. I can't imagine it being so out of whack that it wouldn't run at all.

 

Dim: i have a Q? when the cam is broken in i understand the engine needs to be brought up on rpms to around 2000 and run continuously for about 15-20 min? i cant recall the exact #'s but my buddy did for me while i got out of his way. anyway a WB 02 up and running would be invaluable. if fact i might suggest running open loop and adjusting the A/F to around 13.5/1 while break in occurs. no need to change bin's during event just up FP till you see the A/F that is best for break in of a fresh engine. that way no need to carb it. what A/F is best for break in ?

 

A computer is completely unconstrained. Things can be really off if its not calibrated. It will probably start and run, but I tried the SD on my engine after the headswap just for yucks and all it would do is surge up and down a few times and die (probably lean). Im not saying use the carbeurator for an extended period of time, but just for the intial startup and cam break-in so long as it worked reasonably on a previous engine. Even though a carb can be way off as well, its flow referenced. As far as EFI goes, a flow referenced system is pretty much bolt-on, start up, and go as long as its calibrated properly.

 

:Shrug: I guess whatever AFR it runs reasonably at. 14:1 or so sounds reasonable.

One reason I brought up the carb comment was all the trouble I had on initial break-in way back when. I could barely keep the car running for the 20 minutes or so. It was a real drag with the glowing headers, smoke, and backfiring. Had to shut down in the middle and fiddle around with it. Just my opinion. At the very least, though, Id try to set the timing to what youd use with an HEI dist. to get it going. It may very well not run on the stock timing curves. I think RBob sends out his calibration with the EBL, so it may be close enough for initial startup. Who knows.

 

I am getting a .bin from a guy with a very similar engine to mine. All I need to do is change the BPW constant to match my injector's output and I should be in the neighborhood at least. I'm going to run it a bit on the rich side for break in just to be safe. It should be fine....my cam isn't that big anyway, so it's not like it'll be that far off.