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350 small block build

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4K views 19 replies 5 participants last post by  Craigws14 
#1 ·
I need to start building the engine on my truck. Ive re done basically everything else on the truck and nothing to the engine other than regular maintenance when needed. I plan on keeping the factory T.B.I. injectoin but modifying it (spacer, new injectors, pod spacer ect.) I would also like to get an aftermarket intake manifold.

*** Am i wasting my time keeping the tbi? Are these the best ways to upgrade the tbi if i do keep it??

Other than that and headers what are some decently easy mods and upgrades i can do to this engine.



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#3 ·
so you have one thing going for you, the tbi system should run forever, however, that motor has the worst flowing heads in the history of engines so it'll run forever at 120hp
 
#5 ·
Honestly, yes, you are wasting your time. I had a nice 1992 TBI LO5 rcsb and a nice 1997 rcsb came into the shop and I bought it. m I had both trucks for a while.
They both had 275 60 r15 28" tall tires, both had 3.08 open rear 10 bolts, both were loaded, both were 350s, both had the same trans ratios 700r4 vs. 4l60e.
My girlfriend had a 1997 rcsb, it was work truck with the L35 V8, 3.08 gears, 28" tires

LO5 200hp@4000rpm 290 lb/ft torque@2400rpm
L31 255hp@4600rpm/330lb/fdt torque@ 2800rpm
L35 200hp@4600rpm/260 lb/ft torque@ 2800rpm

All rcsbs, all had 3.08 open diffs, all with same tire heights.

One reason I was looking for an L31 is that my GFs L35 V6 truck would beat my LO5 truck in the 1/4 mile. The LO5 would jump out by a couple lengths out of the hole, but that L35 V6 would out power the LO5 in 3rd gear and be about 3/4s of a length ahead at the finish line.

The LO5 was embarrassed by the L31, in all aspects except top speed, just because the L31 was limited to 98mph and the 92 wasn't. With the limiter removed and with 4.10 gears(swapped out the 3.08s) I had the L31 truck to 124mph, which was with 28" tires, 4.10 gears, 4th gear(0.70:1 OD) revving 4300rpm. I could have pulled more, but I wasn't enjoying the vibrations I was experiencing. I didn't want to find out what its like to throw a driveshaft when its spinning 5600rpm. I did end up throwing the driveshaft going about 60mph where my engine rpm was about 2100rpm, while my driveshaft speed would have been about 2700rpm. The trans extension housing exploded, the trans output shaft sheared off, driveshaft flopped around bend the crossmember and trashing the cats.
Got another 4l60e, driveshaft, fixed damage, backed the truck off of the rack and out of the garage for a test drive. As soon as I got up to about 60mph a vibration set in and by the time I could slow down, the freaking same thing happened again. Extension housing exploded, but this time thank goodness the output shaft stayed in one piece which prevented the d/s from flying around.
I bought a new extension housing, new custom made steel d/s. This time I disassembled the rear end and found out that there was some severe wear on the ring and pinion. The wear was uneven and threw the balance out of whack and sent a harmonic up the shaft.

Basically you are starting with the equivalent of L35 V6 power and spacers and intake manifolds aren't goping to do much except empty your wallet.
My 97 rcsb L31 truck stock ran around 15.9 @ 82-83mph, which would just eek out a win in the 1/4 mile against my buddies 1996 Dodge Ram Pace Truck 360 with the 3.92 rear gears, Mopar performance-headers, exhaust and PCM tuning.
My best run with gears, K&N FIPK, Fastchips PCM tune and Hooker 2462 1hkr headers(these will fit your truck) was a 14.8 et at over 90 mph.

The most mileage I ever got from my TBI 350 was about 450km, while with the L31 I once got 725km, both had the stock rcsb 100 liter tank.

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Here are some setups for your TBI LO5 truck. These come from the HP Books "Chevy Trucks" book printed in the late 90's.

15 seconds
modified air intake system
headers with 3" exhaust
performance pulleys
performance tuned chip
3.73 gears with limited slip/locker
stock or 1800rpm stall converter

14 seconds
same as above with:
blueprinted throttlebody
Edelbrock aluminum intake manifold
performance hydraulic roller cam
roller rocker arms
World, AFR or Corvette aluminum heads with stock 194"/1.50" valves
3.73 or 4.10 gears
MSD ignition box

OR
stockengine ith Whipple, Paton, Vortech or B&M supercharger
custom PROM chip
aux fuel pump
modified air intake system
headers and 3' free flowing exhaust
3.73 gears and posi/LSD/locker

low 14 seconds
stock engine
80-120hp Nirous Oxide injection system
headers with 3" free flowing exhaust
3.73 gears with traction aid(LSD/Locker etc)
MSD 6AL box
aux fuel pump
custom PROM chip

13 second ETs
supercharger with 10+ pounds of boost or 150 hp nirous shot
modified air intake system
performance cylinder heads
performance camshaft
4.10 hgears with traction aid
traction bar/slapper bars
ACCEL superram intake TPI system or similar
custom PROM chip
MSD 6AL ignition

OR

383 stroker engine
Accel Super Ram system or similar
modified air intake system
performance cylinder heads
performance cam
headers and free flowing exhaust
traction bars/slapper bars
custom PROM chip
MSD 6AL system

xxxxxxxxxxxxxxxxxxx

If you need a new engine, I'd get the 4 bolt version of a Vortec 350 p/n 12530283 or the 2 bolt version which is p/n 12530282. Both sell from Summit or similar for $2000.
You get a brand new longblock, the highest flowing GEN 1 heads ever used by GM, forged PM rods, nodular iron crank(stronger than cast iron) and hypereutectic aluminum(high slicon) pistons. Plus you get the modern block that already has all the roller cam guts.
You can literally take this engine, drop it in your truck using the GMPP TBI to Vortec head intake manifold, drop in a new chip and drive. In 1996 GM made a stock TBI/Vortec combo for export vehicles and it was rated at 235hp/340 lb/ft torque. It used the L30/31 Vortec 305/350 191º/196º duration @ 0.050" lift and 0.413"/0.428" lift with 1.5 rockers on a 111º LSA roller camshaft.

Just last year Chev Performance Parts introduced a new GEN 1E crate engine rated at 357hp from 350 cubes. That engine is simply a 4 bolt main 12530283 Vortec replacement engine with this newly released roller camshaft slammed in it.
The new cam has 215º/223º duration @ 0.050" and lift of 0.473"/0.473" on a 112ºLSA.
Under p/n 12677151 for $315.

That cam allows the greatest lift that the Vortec heads will take in stock form. Its a nice little cam and will deliver better fuel economy than the 218/228 LT4 Hotcam.


OR

You can get ahead and drop in a GEn 3 4.8/5.3 or LQ4/Q9 6.0 and with the right cam/heads enjoy a 400-500hp SBC.
Step into the GEN IV world and with the L92/LS3 heads enjoy over 500hp naturally aspirated.


Just some ideas, truthfully though, it is really tough to get cheap performance out of the TBI systems.


peace
Hog
 
#10 ·
Thanks this was very helpful. Definetly going to look into the parts listed. I just know my wau around this truck so well cause ive had it so long and dont really wana to swap out the whole motor or injection system. But everything down to the very last u joint on this truck has been re done. All except the motor, because to be honest it runs perfect so don't fix what aint broke right. I just want to squeeze out ad much power as i can without pulling the whole motor.

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#7 ·
JFC hogg..........maybe let him answer the question on WHY he is building a 350 BEFORE we shove LSx platforms down his throat?
 
#15 ·
How much power are you looking for? For the money to do heads and stuff you're getting awfully close to the cost of just LS swapping.
 
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