ok. i did this a wile ago. I did a search on some truck forums but they told me to post here.

I hve a 88 k1500. it had a 305 tbi. I built a 350 tbi. I had some issues as in i did not know that the old motor was a 305(was told it was a 350). so i ended up by buying a new gm chip and 2 new gm 350 injectors for my truck. the motor still does not have the power that it should. it does dig hard. i have 35" tires 4.56 gears and a built 700r4 built mostly for towing.

The motor is bored .60 over cam heads have some valve work done but no major porting or anything like that. comp ratio is 9.5 to 1 with headers and a dual 2 1/2 .

my truck does not do a burnout. I can smash the gas from a start and it does go. if i try to hold the brakes a little it will just bog. I am not saying that i want to smoke the tires on my truck everyday but If this truck can't do a burnout then maybe I am not reaching the full potential of my motor and my mods. just so you know it does idle well. it does heat up fairly quick. within 5 mins. and I did this swap about 6 years ago. I don't drive the truck that often. honestly I drive less than 5 miles a day with it. but when i do take it around town I would like to know that it is running to its fullest potential.

my question is. should I buy a new chip for the cpu. are my injectors adaquite for the motor? also are the tbi spacers a good idea. thanks for any info.

 

well is the timeing set correctly
i did a 4 wheel pell in a k1500 with a lo5 350
so id assume something isnt set correctly for your truck

 

the timing is a little advanced but it is not to the point of pinging. it is only 2 or 3 degrees. but i drove it today and noticed when I go down the road and i get into it. it feels like I am pulling a leaded trailer all the time. it does stuble around 2 grand or so then pics up a little. but i know something is not right.

 

are you sure its a tbi engine with tbi heads
like say if it has tpi heads the timing needs set to 6*

mess around with timeing till it feels better

my camaro felt the same way when i 1st got it it turned out my timing was set to -4 but it ran smooth but lacked any guts

also

 

yea the motor was a tbi 350 from a truck. it came oil pan to intake manifold. i had messed with the timing. it did make a little difference but nothing great. i forgot to mention i do have an msd 6a with a accell coil. after i installed the msd i tried to change the timing to 0. no luck with power, i had it set to 6 that made a little difference but not alot. so now i am here.

 

honestly you should easily melt the tires off with thouse gears and even a tired 350 or 305 for that matter

my tired 305 melts the tires off my camaro with 2.73 gears so maybe you didnt get the correct injectors or something cause man if timeing isnt the issue im not sure what would be

now for me i would start checking for clogs in the pipes or something made a nest in the aircleaner type deal cause really the lo5 engines may not have been the ultimate in proformance but its not like there complete dogs


maybe you need an some extra fuel pressure from it being over bored
honestly its got to be something small like they gave you the wrong part or something along thouse lines

take it for a nice long drive like 60 miles or so work the bugs out drive it a bit more often and for longer bursts

i would say useing aftermarket bolt ons and what are not worth it yet as youre not makeing the stock potential of this engine

 

yea i was not going to add anymore bolt ons i already have what I want for the most part. I thought when i added the msd that it would work out any issues i had with timing and so forth. I am starting to beleive that I am going to need to maybe upgrade to a tpi pump and a fpr. I would hate to buy new injectors again. but if i have to i have to. thanks for your info.

 

I agree, even a tired LO3 305 should melt the tires off. Something is definately wrong. Here is how my tired 200,000 mile 305 ran.

1983 305, TBI setup, headers, duals, 700r4, 3.08 gears, P255/70/R15s.

http://www.youtube.com/watch?v=Oi_n0goatA8

 

i wish my truck could do that.

i don't even have 30k on my new motor. i have to have some fuel issues or something.

 

I noticed you mentioned something about a cam. How big is it? I really don't even need to ask that, if it's much bigger than stock at all it's going to cause problems unless you tune the motor properly.

 

the cam is not that radical. it only has .440 lift inkate 441 exht. I just did my timing using the caccum method. i hooked it up to the tbi in front. i got 21 lbs of merc. i thought that is high but i dunno. after that i could spin the tires with one foot on the brake. when it swithched to second it just bogged out. i took it on the street and turned a corner and hammered it. it spun for like 1 sec then bogged and took off.