Welcome to TBICHIPS.COM
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| Below is mainly geared for the SBC V8 guys. The 4.3L
guys, I recommend the V8 Swap which is not difficult at all and will yield the most bang
for the buck but if you must run the 4.3L then check out www.tbi-superchargers.com and consider vortec
4.3L heads or both. I have info on the V8 swap under Frequently Asked ?. 454
guys. I am creating a new page for you. 454SS This is for
both the 454SS guys and the heavyduty trucks. I don't have as much experience with
these but I will share what I know. If anybody has some info they care to share, I
will gladly post. Ok. Trucks aren't quite as bad as the Cars in exhaust design. (cam,
intake, airfilter, heads and exhaust). I tried to put these in the order of
importance. Also, if this all seems overwhelming just email me at sales@tbichips.com with what you have and what you
would like to do and I will make some recommendations on how to achieve your goal. The cam in the TBI engine is just plain AWFUL. Specs on Stock TBI cam is .050" tappet lift (intake/exhaust) is 179/194; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is .350/.384. Valve springs are also VERY important due to the stock ones having a redline of 4500 rpm. With the proper cam and springs the redline can easily reach 6000rpm. Intake and cam is worth a good 40hp as long as you did the other mods too. I have listed a bunch of new cams at the bottom of the page. This should provide you with a sufficient assortment of cams for whatever power range you want for your motor. If you still don't know what cam to use, email me at sales@tbichips.com all of your engine and vehicle details and I will gladly recommend a cam for you. 2. Rocker arms. I just recently decided to add this in here since I found that Pace Parts http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=178072 has a cheap set of roller tip self aligning 1.6 rocker arms. This will allow you to run one of the milder cams such as Edelbrock 2102 or Comp 12-249-4 cam for better low end torque and increase the lift to give a little more power. Just be careful on GM heads not to exceed .480 lift or bad things will happen to your valve train. Take the lift numbers below and divide them by 1.5 which will give you cam lift and then multiply by 1.6 which will give you the lift with 1.6 rockers. 3. The exhaust. I recently moved the exhaust up on the priority list after seeing the dyno results on my Black Magic project truck. Change the WHOLE thing from the engine back. I recommend getting the headers and catback system any brand should do. I used these stainless headers http://motors.search.ebay.com/stainless-truck-headers-88 with Dynamax cat back. Get a 3" hi-flow catalytic converter. You can get them for about $60 on ebay. This modification is good for a solid 25hp. I have used the Summit Racing brand CATBACK on my budget vortec project and the kit could have been better. the tail pipes didn't fit well but for $160 its not horrible. If you use a long full length header, you need to use a 3 wire 02 which I have wiring info on the FAQ section. The exhaust configuration that I really like is what we used on the Blue Whale project which utilized standard shorty headers and then I had 2 2.25" pipes run as true duals for better low end torque and fed 2 mini flowmonster cats into a dynomax WLK-17552 muffler and then ran the tail pipes on out the back. Check out thiis exhaust combo I put together with reasonable parts from Summit Racing. http://store.summitracing.com/partdetail.asp?autofilter=1&part=BIG%2D11504YFLT&N=700+115&autoview=sku and http://store.summitracing.com/partdetail.asp?autofilter=1&part=BIG%2D11504FLT&N=700+115&autoview=sku with dynomax cat back http://store.summitracing.com/partdetail.asp?autofilter=1&part=WLK%2D17324&N=700+4294908216+4294925005+115&autoview=sku If you need cats and I highly recommend you use them, do a search on ebay for FLOWMONSTER CAT and I used these on the blue whale project and the black magic truck and they work great and they are CHEAP and that is the kind of combo I like. To see what affects decent exhaust can have on your engine project, check out the black magic project on the left and look at the dyno results of just an exhaust change. 4. The Heads. The TBI heads are the worst flowing heads GM ever released. So the best bang for the buck is the these aluminum heads from whiteperformance1. They flow well and are not real expensive for an aftermarket head. The GM Vortec head is also a good choice but does require a special intake and lots of EGR work if you need EGR to remain emission legal. These heads are good for a solid 50hp. Another good reasonably priced set of heads that will work nicely without special intakes on a TBI motor is a set of DART 165 iron heads. They flow well and the price isn't bad. The DART 180's also flow well and have a better exhaust flow than many small block heads and so I would keep the cams intake and exhaust duration tighter together. ALSO check out http://www.chevyhiperformance.com/techarticles/41598/index4.html for some air flow information that can help you decide on the heads you want to run. Next to the cam this is the most important choice. Compression ratios and pistons and all that stuff are not near as important as the head and cam choice. That decision will make or break your engine project and you wallet if your not careful. Also, tow beasts and 4x4 guys. This may come as a shock but I may not recommend changing the heads on those vehicles. Up to 3500 rpms the TBI heads will make pretty much the same power and torque as a good aftermarket set of heads. Its from 3500 rpms on up that the TBI heads start falling off quickly. Well most 4x4s and tow beasts are more concerned about low end torque than having 500hp at 6500 rpms where they can't use that power. The comp cams 12-249-4 cam along with the 1.6 rockers that I mentioned on item 2 will make really good power and torque on a 350 TBI motor up to 4000 rpms. I would then recommend if your building a torque motor that instead of spending the money on a set of better heads that a 383 stroker kit (BALANCED) would be a better choice. While the extra cubes won't significantly add to your horsepower numbers due to the heads not flowing enough air to reach a good high rpm number, the motor will have over 400lbs of torque and still get good gas mileage as TBI heads are rather fuel efficient and a cam that is designed to work well with the combo such as the comp 249 cam and you will have 454 torque with 350 gas mileage. Actually the TBI 454's only made 380lbs of torque which is pathetic for a 454. Check out the heads on http://www.rhsheads.com/Products/Heads/PT-SBC.asp
Vortec heads that flow more than stock vortecs and have a bolt pattern for a standard
intake and the price isn't much more than a new stock set of vortecs. I haven't had
a chance to use them but they should be great for the $$. 5. The air cleaner. http://www.thirdgen.org/newdesign/tech/ultimatetbi.shtml The baffle on the TBI Truck is too small for a 2.8L V6 much less a 5.7L V8. Or you can run with a 3" tall 14" diameter open element filter with a flat base. Also toss the choke collar (has nothing to do with choke like a carburetor, its choke as in restriction) ,if you run the open element filter with flat base, that is between the TBI and the air cleaner assembly. Good for around 10hp Here are the summit racing air filters that I use and recommend. SUM-239421 14 in. diameter, chrome, flat base, 2in. element, air cleaner assembly for tight clearance hoods SUM-239431 14 in. diameter, chrome, flat base, 3in. element, air cleaner assembly SUM-239441 14 in. diameter, chrome, flat base, 4in. element, air cleaner assembly Now open elements are NOT really recommended for 4x4's (water holes can drown that open element filter assembly) or you may want to spend a little more money for colder air for more power gains. If either is the case then you need the Hypertech CFM Powercharger http://www.cfm-tech.com/catalog/air_intake_-_hypertech_power_charger_-_4_3_5_0_5_7_full_size_truck_549430.htm and a http://www.cfm-tech.com/catalog/air_intake_-_cold_air_intake_tube_-_full_size_gm_tbi_truck-_new_product____3280272.htm with a K&N filter for the stock air cleaner assembly.
If your going going to build a motor for over 270hp then you need more than the ultimate mods. Have one of these 2 companies bore your stock throttle body out for more air flow. www.rvmorsemachine.com and www.xtremefi.com are the 2 companies that I am aware of that do this work and I have had both companies bore throttle bodies for me. The stock 305 and 350 TBI unit has 2 (1 11/16") bores which flow 450 cfm of air. Compared to a 650 Holley carb that is bad. Holley does make an aftermarket TBI unit for the truck that will work with the cars with a little work and it has 52mm 2" bores and 65lb/hr injectors but Holley throttle bodies are plagued with bad injectors so be careful if buying one used and they are pricey new. However it flows 670 cfm of air and has a 52mm 2" bore. I know longer recommend using a 454 throttle body. Too many issues with different TPS sensor and rewiring the IAC valve and the throttle bodies just being worn out which is the BIGGEST problem. Get your TBI bored out at www.xtremefi.com or www.rvmorsemachine.com It may cost a little more but I feel you will have less headaches.
Instead of using adjustable fuel pressure regulators which has been all the rage in the past. I have tested several springs and had a custom spring http://motors.search.ebay.com/18-psi-spring made that will yield 17-18psi at a much lower cost than buying a regulator and a fuel pressure gauge to set that regulator by. This way you can just slap the spring in and go and its a one time disassembly of the throttle body instead of 3 or 4 times to get the fuel pressure correct. Also, a new fuel pump http://motors.search.ebay.com/?from=R40&satitle=dynapex+fuel+pump is VERY important as the stocker is only good for about 270hp and won't maintain any higher fuel pressure. It can barely keep the fuel pressure maintained for the stock 9-12 psi. So what size injector or fuel pressure combo to use? Well here is a basic guideline. Stock 210hp 350 V8 up to 240hp the stock 55lb 350 truck injectors at the factory 9-12psi is fine. from 240hp to 260hp the fuel pressure should be bumped up to 13-14psi on stock 350 truck injectors which will change their flow rating to 60lb/hr From 270hp to 320hp you need to change the fuel pump as the stock pump can't maintain pressure over 270hp and you need to run 18psi on the 350 truck injectors for a flow rate of 68lb/hr From 320-360hp this is where you should be looking at the 454 injectors and run them at the 13psi for their 82lb/hr flow rate. You can run them at the stock 9-12psi and still be fine for this power range. From 360-400hp you need to bump the fuel pressure up on the 454 injectors to the 18 psi to increase their flow rate to 96lb/hr. For over 400hp you really should be looking at alternative injection system but for up to 450hp you would need to run 24psi of fuel pressure to increase the lb/hr rating on 454 injectors to 112lb/hr and that is as much pressure as I recommend applying to a set of TBI injectors.
9. Gears. One of the best ways to get the power to the ground is through gearing. A 3.73-4.10 gear makes a nice streetable rearend gear. Some of the trucks came with 2.73 and some with 3.08. These are terrible gears. I feel that the 3.42 gear is tolerable in a 2wd especially if its pretty stock. check out http://www.angelfire.com/fl/procrastination/rear.html and play with that calculator. I like my trucks to run around 2000-2400 rpms at 70mph in overdrive. Less than 2000 and you don't have any power in overdrive and it just shifts to 3rd at the least little thing. Over 2400 will make more power but gas mileage will suffer. In that range and the gas mileage will be fine. For speedo calibration for a tire and gear change go to www.tbichips.com/drac for 4L60E,4L80E or 5spd trucks and http://www.transmissioncenter.net/speedometer_calibration_______va.htm for 4L60 700R4 trucks. 10. There is always the supercharger. Check out www.tbi-superchargers.com for some real fun. 11. Torque converter for you automatic lovers. The stock V8 converter stalls at 1400 rpm which is very low. The 95+ S10 4.3L V6 torque converter stalls 2000-2200 rpm. That 600 rpms will help keep your engine in its powerband and thus make it faster. If you go with a cam with over 212 duration @ .050" then a higher stall would be advised for most street applications. The 2000 stall is a good upgrade that won't screw up your gas mileage, burn up your trans, break the budget, or be unbearable on the street. 4x4 guys, I typically don't recommend the higher stall converter. If you go off roading that extra converter slippage can be a nuisance. 12. Check Out Blueprint engines http://www.blueprintengines.com/popular_configurations/index.html?topic=options&pcsci=5
They have some nice long block 383's made for TBI now. Also they carry a nice
shortblock if you want to build on your own 383. Check Out Blueprints 383 short block
$2000 for a nice base for your 383 project. http://www.blueprintengines.com/popular_configurations/index.html?topic=specs&pc_id=78
RECOMMENDED CAMS I have removed the Summit racing cams recently due to a lot of lifter issues with these cams. Crane cams Summit Part Number: CRN-113932 Summit Part Number: CRN-113934 Cheapy Sealed Power cams CS1014R I haven't tried this cam yet but I may give the 1105R a try on project Plum Simple Also Northern Autoparts Northern Auto Parts has the sealed power cams complete with timing chain and gears as well as the cam and lifters as a kit for under $100. Can't beat that for a budget build.
COMP CAMS As you can see below as the duration gets higher so must the lobe separation angle.
Choose one that provides the rpm range that you want your engine to run in. For you 93-95 TBI trucks, I can set the rev limiter to match the redline of those cams and the 4L60E automatics, I can set the shift points to match the powerband of those cams. All 87+ cars got roller cams but the trucks didn't get one until 1996 (Vortec). The trucks have all the provisions for the roller equipment but just didn't get the parts. Part list for converting to roller cam should you want to go that route. GMPP P/N 12371043 = timing chain/gears and roller cam retaining plate
kit (1st and 2nd design plates!) |
One of my customers found that
Turbo city now offers a pigtail to use the 454 throttle bodies on the 4.3, 305, or 350
wiring harness. 