Simple TBI build
 

Hello All,

I thought i would share my new TBI build and results with the forum. I have searched a ton and finally decided to keep it simple.


I use my truck as a DD and to tow my 8500lb camper in the summer. Most builds talk about max HP/torque. My bigger concern was usable torque at 2500-3500 rpm and at <half throttle. You can't tow at WOT and 5k rpm for long. For that reason I decided to keep the swirl port heads, My thought is velocity is what i am after not big flow numbers. I fully understand the limitations of these heads but for now i wanted to be back running this spring and not get into fueling and programming issues.

http://i1338.photobucket.com/albums/...pskurmqz0e.jpg

I want to keep the motor around 2300 at 65 in OD and up to 3100 in third at a down shift. The idea is to keep it in the max torque range while working. For this build there is little value in numbers over 3500. I hope i will still get 15+ mpg around town and 10-12 towing. If i can't get there, i will build a BB and sell this motor at a later date. The cost of to build a 383 kept growing so this was alternative for now.

Overview is
5.7 crate GM
lunati cam
full length hedmans
4l80
small block 4l80 converter (stalls higher than the BB version)
4.56 or 4.88s

Anyhoo, Here it is,, I will post the pics and specs as it develops and a bin file for the computer at the end if needed.

This is my OEM TBI 5.7 I sold the long block for 300 on CL.

http://i1338.photobucket.com/albums/...pshzidctrg.jpg



I bought a new GM crate 12568758 from summit for 1640 free shipping, no tax. (-300 for the original) new motor cost 1340. It is hard to touch that number with a local machine shop. It has hypereutectic pistons and a CR of 9.4

http://www.summitracing.com/parts/na...make/chevrolet

http://i1338.photobucket.com/albums/...pshvkvkflg.jpg



It is a roller block but i am staying flat tappet. I am installing a Lunati cam (113$) lift .437/.454 Duration 250/256 and using the GM lifters I was going to polish the heads a little but they look decent enough. I do not want to open them up because it is the velocity at 1/2 throttle i need. The longer duration should should help.

http://www.lunatipower.com/Product.aspx?id=1981

http://i1338.photobucket.com/albums/...pspahc1zkj.jpg



I know I could go roller but the point of this is to make my 7.4 vortec numbers (Vortec L29 454 290 hp 410 lb/ft torque) without a bunch of money and tuning. I doubt i will get there but that motor towed great and still got respectable mileage.



This is the truck it is going in.

http://i1338.photobucket.com/albums/...ps4ifidshs.jpg


If you have any input on parts,,, please advise, If you are interested in the outcome, let me know and I will continue to update.

Chris

Re: Simple TBI build
 

I'm in for the build

Re: Simple TBI build
 

Build looks good but I would have considered the GMPP Ramjet 350 cam. I dont know that it would meet your torque goals with the swirl port heads though but that Lunati cam is a strong one and should perform well. I doubt you will regret using it.

I know its a heavy burban but my buddys 91 K5 with a TBI 350/700R4, 4.11`s and I think 33" tires would get 10 mpg towing or not so you should be close.

Re: Simple TBI build
 

Very nice/clean ride! Are those 31" tires? 4.10's will put you in the 2200 rpm range at 65 with the 4L80E's .75 OD. I would go 4.10's

The cam choice is a nice pick for the application spec wise.

I would go hydraulic roller. You can get used lifters, guides, spider, and pushrods fairly cheap on Ebay. Chevrolet Performance makes a 3 piece single roller timing set that includes the camshaft retainer and bolts for cheap.

I have used that ramjet cam in stock TBI applications with no additional PROM tuning and it works fine.

Re: Simple TBI build
 

The tires are 33s but i might put on 35s in the future.

If i decide to go roller in the future, I will probably buy some after market heads like summit or edlebrocks keeping the intake runner at 165-170 max.

Re: Simple TBI build
 

4.11s and 33s work back to about 3.73s I am hoping to gain tow-ability with the lower gears.

Re: Simple TBI build
 

Then 4.56's would be my choice for 33"-35" tall tires

Re: Simple TBI build
 

I'd go hydraulic roller, it helps efficiency a little and makes oil choices far less important. Modern oils aren't great for flat tappet. I'm not suggesting an aggressive profile, though.

I'd also consider an aluminum intake manifold, they can be had pretty cheap.

Re: Simple TBI build
 

Yeah, if you're gonna change the cam, why not a roller? Using a flat tappet cam is kind of like ordering a new car and putting bias ply tires on it.

The RamJet cam would be a good choice for your RPM range and torque requirements. The earlier closing intake valve means lots more cylinder pressure (and torque) than the Lunati cam, and probably a wider power band. My 82 pickup has a 355 with a take-out Ramjet cam ($120) + GM roller lifters ($125), so it's not prohibitively expensive, even with the new timing set, cam retainer plate, and lifter retainers and "spiders".

However, even the most torquey (torquiest?) 350 won't come come close to matching the 454's torque. Not with 104 fewer cubes, even if you rev the 350 to the moon. That said, I once had a 350 with a small Crane flat tappet cam (194/204/104) in a 69 pickup. That thing made massive torque in the 2500-3500 RPM range, even though it ran out of steam above 4000 RPM. I never towed anything heavy, but it would pull a 2000+ lb trailer over an 8,000 ft Colorado pass at WAY above the speed limit.

Re: Simple TBI build
 

I'm in.

Re: Simple TBI build
 

A well set up moderate roller 350 intended for truck use can certainly make more power than a smog dog 454, and likely tow about as well, but it's hard to get the off idle torque of the bigblock.

Re: Simple TBI build
 

Hello,
I have a header question while waiting on a few parts.

I would like to go 1.5 inch primary and 2.5 collector but i can not get an answer as to what might fit. Being the V series trucks, i am not sure if it is left out sometimes by accident and the tech phone guys have no real answer.

Will a header from the next generation fit a square body (I know it might have the egr tube and maybe that is why it is not listed for my truck) and/or will a 2wd header fit?

Thanks,

http://www.summitracing.com/parts/su...00?prefilter=1

Re: Simple TBI build
 

I'm with you on the roller cam but i am going to try simple first. I thought about the vortec crate at 2K but then i had egr stuff and fuel tables.

If i do the tbi crate, and go roller, i would need cam, lifters, pushods (600 ish). If i can't get the numbers from this build, I might go all out with aluminum heads and a roller set up. I just thought for the price this might be fun to try out and if it runs well it might help out other TBI truck owners.

Re: Simple TBI build
 

Curious to see where you take it. I always felt the stock TBI motor worked just fine for off-roading.

Re: Simple TBI build
 

BONE HEAD MOVE,

When i sold my old motor i left the oil filter/cooler adapter on it. I have can not locate a source for the OEM style mount (two bolts) with the cooling lines exiting the side. Are the OEM also a two piece unit?

There are 100s of aftermarket stuff but I would like the original if possible.

Thanks,

Re: Simple TBI build
 

Aftermarket oil cooler set-ups come w/the adapter. When I rebuilt my big block, I ordered 2 new cooler set-ups. One to replace the factory oil cooler & a 2nd to put inline for the trans. The way they mounted was just like the OE unit. I can take a look & see if I still have an extra.

Re: Simple TBI build
 

this?

http://www.ebay.com/itm/BBC-SBC-OIL-...NTIfW3&vxp=mtr

Re: Simple TBI build
 

Magic,,, I try to search ebay and never find what i am looking for. I just tried again and that parts will not come up unless i have the part number.

thanks for the link.

Chris

Re: Simple TBI build
 

Sometimes eBay's search function is finicky. I didn't find it with the search actually, I frequent that seller's page because his shop is local and I bought some heads from him recently. I remembered seeing the adapter and checked his page to see if he still had it.

Also in case you need it, Dorman 82560 is a part no. for a kit that should have the right sized o ring for the adapter. and it comes with a the small rings that worked on the cooler lines as well. mines an 83 k3500 with a 454, but I think the parts are all the same.

Re: Simple TBI build
 

Couple of things to reconsider, first as a few other's have mentioned I'd stick with a roller lifter cam and second I'd port match the intake to the head's both those will help a lot with fuel milage.

I had a '92 S10 with a 4.3 that I pulled a 24' bumper pull camper and the engine was a stock CPI 200HP 4.3 from a 94' blazer but I port matched the TBI manifold to the heads and opened up the manifold runners a bit nothing crazy and that l'il truck pulled like a mule all day @ 2500 to 3300. I wanna say with a 3.73 rear I can't remember.

Re: Simple TBI build
 

The headers and gaskets are here today and I am going to take a look at that. The hedmans are 1 5/8 and the head ports are 1 3/8. I am not sure if opening the heads up will harm more than help. I also ordered a set of 1 1/5 summit headers. If they fit well i am going to run them and not the hedmans.

I would like to polish some and smooth the bowls but I just can get into that at this time. If I can not get the performance needed, the next project after this summer will be to go new heads and roller.

I am hoping the men at Lunati know there stuff and the opening events of my valves are timed to maximize the low end advertisement. I get the value in a roller but at this lift and rpm there might be little to gain for the extra ~600$. I guess i will find out the hard way.


When i raced as a kid, I ran a pontiac 400 near bone stock, iron manifolds, cat, single exhaust, factory rubber with 3.54 gears and it would go 13.58 day and night. On the street in 1985 that was pretty fast for a dd to high school. I had friends going faster (12.90s) And some in the 11s, but man they spent some money. Anyway, this is more of a lets see what happens. Dynos and driving are two different animals.

Re: Simple TBI build
 

In for this build. I'm getting ready to start my swap in a few weeks and it'll be nice to see how yours turns out. Great looking Suburban

Re: Simple TBI build
 

What are you swapping in?

Re: Simple TBI build
 

I just hope you don't end up with a lobe going flat and metal particles circulating throughout the engine. Its not about that RamJet cam being superior performance wise, its about reliability.

If you are determined to use a flat tappet in todays world, please use generous amounts of PASTE lube such as made by Crane. ( NOT THE RED JUNK THAN RUNS OFF OVER NIGHT). Pre lube engine, use quality lifters such as Johnson or Genuine GM. Cold set the valves on the stand, use a good oil such as Valvoline VR1 in the silver bottle(10W30), Stab distributor correct, coolant in, no leaks, have everything in order to fire up ASAP and run for 15-20 minutes varying RPM from 2000-2500.

Good luck!

Re: Simple TBI build
 

TBI update,

installed the cam today, here are the specs

http://i1338.photobucket.com/albums/...psdhcrpcex.jpg

if you don't have one of these, i highly recommend it, i have no idea how installed cams as a kid, I must of jacked up some bearings.

http://i1338.photobucket.com/albums/...psyls5d8dm.jpg


I did grind a little on the intake, One runner was a big offender, the rest were minor. The swirl port is still the big restriction so i just touched it up some.

http://i1338.photobucket.com/albums/...pshdofznou.jpghttp://i1338.photobucket.com/albums/...psuzzyxww7.jpghttp://i1338.photobucket.com/albums/...pscx3xv7rs.jpghttp://i1338.photobucket.com/albums/...psm8fesphc.jpg

crazy enough, the OEM heads were a lot cleaner than the intake so i just could not justify removing them, all the disassembly just for negligible gains.

http://i1338.photobucket.com/albums/...psia5h8kra.jpg
http://i1338.photobucket.com/albums/...psabooks6k.jpg

The other side was exact, the scribe did not even leave a mark,, go figure?


The have mixed feelings about the intake,, It is really no different than stock and the only reason i bought it was because I did not want to risk a crack in the old one and by the time i surfaced and cleaned i felt it wasn't worth it.

On the new intake, the holes to mount the the map/sensor stuff is off a little, I had to bend the bracket narrower and also put a small spacer under the from bolt.
http://i1338.photobucket.com/albums/...ps3ksaqvmz.jpg

Also the threaded hole in the front for accessory supports is missing, It looks like it is cast in place, just not drilled and tapped. Not a biggie if you have a tap set, but it would suck to have to buy a 3/8 tap and bit just for that.

http://i1338.photobucket.com/albums/...ps1qexd45u.jpg

I am going to mock up the headers tomorrow on the stand and see which ones have motor mount/ plug wire/ starter / oil filter issues.


It is easy to want to do more to this motor but i am trying to have it run under the original chip without issue,
I can burn chips and program, just thought i would try this route first. If this can not get it done, I will most likely install a set of after market heads and it will make plenty of power.