i just had a friend give me his tbi set up off his 89 fire chicken with the lo3 heads... i am going to port and polish them myself. i also want to put 1.6 rr on the intake side. i have seen several articles where it showed an improvement by mixing them.
i was wondering if there was a 350 that came stock with 1.6 rr? i did a search but didn't get any good info.
i am also going to make a spacer that has the center of the bore filed down and radiused so that the cylinders will draw air from both sides of the cylinder bank.
i may also experiment with the tb to see if there is another way to get the fuel into it without the injector pod sitting directly in the airflow path i may even bore the tb over a bit. i did the ultimate tb mods about 1 year ago and did fine with that. if anyone has any crazy wierd ideas that might work cheaply... i might try them.
i am going to use this engine until it blows chunks then put in a 350... or a 383...

 

the L03 heads are useless... Itll take forever to grind out the ramps in the intake runners. Go get a set of L69/LB9 heads and work with those instead. Theyre a much better casting to start with. IIRC none of the older stock SBC's that youll typically run into in the yard came with 1.6 ratio rockers. The LT4's had higher ratio rockers but your unlikely to see them. Donno about the LT1's though, think theyre just standard ratio. You can get a set for not too much from summit or jegs, though. Just make sure whatever you get is made out of steel. Dont get a set of full roller rockers if theyre made of aluminum. It has a limited fatigue life. As for the tbi, you could get a single plane inake instead. It would probably work better then guessing on how large to make the hole in the divider. As for the tbi, i think it can be carried out to 48 mm or so. After that, youll start running into all the critical passages. Good luck and happy modding...

 

SORRY... i know the l69/lb9 heads are better... but these are the stock lo3 heads so i am going to do them myself... as i said i am going to do this as an experiment. also i have already made 1 spacer and you don't need to guess at the holes. you trace the tb gasket onto the material and cut... or i can buy the one from cfm tech for 79.00 made from aluminum. it looks real nice i will try to post a pic...

 

here,...

 

impressive. out of curiosity, why just put 1.6s on the intake valves? i know more lift is good, but why not put them on both sides? also i thought sbc's were exhaust restricted, so if you were going to do 1.6s on only intake/exhaust valves wouldnt you see more gain from the exuast valves? just a thought/question

 

i am refering to a test done in chevy highperformance mag... they used 1.6 intake and 1.5 exaust and it made i think 4 more hp and 6 more torque or something like that??? i'll have to find the article again... i am also debating whether or not to shell out the money for the cfm one or make one from this real thick plastic composite i have??? i don't know if it will take the heat??? i put fuel on it and it had no problems!!! i just don't know how hot it can get??? it is pretty heavy duty though and it is real thick 1 inch... i have hood clearance so that won't be an issue.

 

yes nick nailed it, typicly you put the 1.6's on teh exaust side, not the intake side.

but with all the dual pattern cams now, they make up for the exaust side by running more duration. i think you best gains are going to be with 1.6's on the exaust, or a nice dual pattern cam.

 

i'll look for the article again maybe my brain was fried that day...??? .
i could have sworn they said intake side... but i know the intake valve is bigger so it would help your exhaust...

 

I was reffering to the opening in the divider. The area can be quite critical to achieve the proper resonance to help reinforce the effect. You probably could just use the one pictured as a teplate to decide how large the opening should be in the spacer that youll be making.

my bad about the heads... Didnt know your doing it to see how far you can take them. How much do you plan to remove from the heads? The whole ramp? Or are you jsut going to clean up the runners and the bowls?

 

umm, what cam?

because if its just the stock L03 cam, you will get more power by running 1.6s on all of them


mostly because the cam is TINY. once you get a decient sized cam, then you can experiment with that and see some results...




as for somthing to try, why not try using 2 TBIs and have a dual quad looking intake.....

 

i forgot to put my sig in this one but i have an lt`1 cam... its ben in for a few months now!!

 

i have been wondering about dual tbis. could you just use another computer, and splice into everything before the original one so that both could use the same sensors, or like a piggy back set up just for the extra tb. or could one computer run them both? i figure one computer couldnt do the job but it was worth asking about. what about using a crossfire computer to run dual model 220s?

 

due the injector impedance, you would need a 2nd injector driver. there is a guy in the DIY PROM board that is doing something close to this, but using a 4bbl TBI with 4 injectors.

someone also brought up the idea of using relays for this, not sure if anything ever came of him doing this though.

 

I THOUGHT OF THIS TOO BUT i am not sure about it...??? it seems too much like cross fire injection...

 

but on a dual quad intake..... could be interesting

 

oh i think i am going to remove the whole ramp if i can...??? i still have to get a spring compressor to get the valves out. plus i got to pull the studs out and i have a tap and dye kit so i will cut the threads my self... does anyone know which size to use???

 

huh

 

check page two of posts. look for the posting: 350 tpi exhaust manifolds. dewey posted a link there for some screw in rocker studs. cheap too.

 

In addition to cutting the threads, youll should also have the surfaces taht the studs will be mating to machined flat. As for my opinion on the dual tbi setup, its difficult on the smaller displacement motors because of the low demands at idle and part throttle. Someone is running a dual tbi setup on a bb but i cant remember his SN. You also have to use a driver for the injectors as the output from the ecm is more of a waveform. The injectors are first fed a peak current to get them to open rapidly and then a smaller current to keep them open for the desired pulsewidth. This is done to help keep the injectors as well as the power transisters in the ecm cool. If you notice, on the side of the injectors there are actually small weep holes that allow gas to circulate through teh injector and keep it cool sice they already generate a good deal of heat.

 

only if you are running studs with jam nuts. if you get the mr. gasket street studs, you do not need them. i have installed them on L98 heads with a .525 lift cam, and they held like champs.

 

really... i was told by some that they only consider the mr. gasket ones as a temperary fix rather then a long term solution to running with high lifts and spring pressures. Theyre a pretty good solution then if they hold up.

 

if you can pull the heads, i would suggest ARP studs with jam nuts too, but if pulling the heads, and going to a machine shop are out of picture, the mr gaskets will work. i actualy tapped and put a set on, with the heads on the assimbled eninge. that is the really nice part.

 

hmmmm.... well how cheap are the mr. gasket ones?

 

just a couple bucks a piece.

 

i think like $39 for all