I have searched, but still have some specific questions.

After reading posts on this subject, I am leaning towards replacing the dead 305 tpi with a 350 tpi.

specifics on computer mods/ replacement, any additions?
from tpiparts.net: Injectors: $335 for 22 lb, Knock Sensor: $49, ESC Module: $85, PROM reprogramming: $65, Total: $534
The 19lb injectors can be used with re-programmed prom...
Total: $199

The newly installed Edelbrock TES headers will also fit... pn: 68722

Any recommendations on components?
pistons
heads
cam (1986 roller-lifter cam issues?)
other

How about finding a 350 locally. Will just about any donor due? what years should i stick to?

Looking for 300+hp net due to budget considerations.

Thanks!

 

I would think an adjustable fuel pressure regulator would be key if using the 19 lb injectors. It's a good tuning tool with either.

Pistons will depend upon heads. Roller lifters with an '86-earlier block is prohibitively expensive for the return on investment.

Assuming you use your '86 305 TPI heads (which isn't a bad idea): Rebuild as necessary, have the intakes cut for 1.94" valves, do basic port clean-up (especially in the short side radius area, aka "pocket porting"). Use pistons with about 12cc of dish/valve relief. Choose head gasket based on how far down the pistons are in the hole (aka "deck height") to get around .035"-.040" clearance between the top of the piston and the surface of the head (aka "quench height"). Comp XE262-ish cam, flat tappet.

Most any 350 shortblock will do as long as it cleans up with less than .060" overbore and doesn't have any starter mount hole issues, lifter bore straightness issues, or cracks (in the lifter valley is pretty common). Mid-80's & up blocks tend to be of better quality.

 

Five7Kid... Thanks!

more questions... to anyone who might help...

I've read quite a few suggestions by you in this forum. I've read your recommendations on sticking with the 305 head, but open intake to 1.96"... sounds good.

I would shoot for a compression ratio of 9.5... Does the 305 head chamber contain less volume than the 350 head chamber? I thought the stock 305 pistons were flat, so your dish suggestion would lower the compression ratio, all things being equal.

Why 35-40 mil deck height? sounds like a lot....

You're suggesting to replace the existing pressure regulator, which is set at a fixed pressure, with an adjustable? I think the pump puts out 45 psi... what is the stock pressure regulator set at?

I asked about roller lifters because I thought I could use a 1987 350 block or newer that would accept roller lifters. For a daily driver, I'm not sure what the roller lifter buys. My impression is that the roller allows for greater cam lift?

I looked at your suggested Comp EX262... that is for 1987-1998. What happened between 1986 and 1987? What determines the year that I would go by? For instance, if I find an 1989 350 block, then use my 1986 305 heads.

I still have not found a local 350 block. What are your thoughts on buying a 350 short block crate and using my rebuilt 305 heads. The problem that I have with crates is choosing components. By the time the core and shipping and any upgrade options are added up, a local shop could build according to my wish list, at the same or slightly less. I'm looking at stock 350 crates from varous outlets for around $900. Usually, 300 core and 200 shipping, so real cost is about $1400 with no choice in components.

Would I need a new a high-pressure pump inside the gas tank. Replacing that pump sound like a pain, but would I use the same pump?

 

after much chewing....

rebuild the 305... sorry....

lowest cost route, highest probability of success, most predictable results...

goals: timely rebuild and re-install, no computer problems, solid rebuild, 250+hp with headers and custom programming for my daily driver...

plan: to re-work the heads... should I still use the larger vavles (intake 1.94, exhust 1.5?), heavier duty springs, high flow oil pump, a double timing chain, synthetic oil...

suggestions?

any cam recommedations beside the com listed above?

 

The 305 chamber is 58cc vs. the L98 350 TPI 64cc. The '86 305 TPI had 9.5:1 CR, after that it was 9.3:1 with a slight dish in the pistons for both 305's and 350's.

The .040" is the total of deck height and head gasket. It's the ideal-ish range to get the highest compression with least detonation for a given octane. It's what you should shoot for regardless of 305, 350, CR, etc. Stock is typically .025-.040" in the hole, plus .015-.020" for the head gasket, so what I'm talking about is actually less than that.

The Comp XE cam series is available in both flat tappet and factory roller lifter type (called "XR" if roller lifter). Roller lifters is what happened in 1987. The 260-ish version works well with TPI and stock stall torque converter.

You'll probably find that cost and down-time will be lowest if you go with a shortblock. The L31 350 shortblock from GM is a pretty good choice, the piston dish is right what you need for 305 heads. You can put either a flat tappet or roller lifter cam in it, but since you've got flat tappet in your '86, that would be the least expensive route. 350 vs 305 is really a bang-for-buck thing, although down-time is also a factor in my mind.

For the heads and/or rebuild, everything you mentioned except the high volume (high flow, you said) oil pump. Standard volume is just fine. Synthetic oil only after cam/ring break-in.

The 305 and 350 TPI fuel pumps were the same parts. No need to change it until it wears out.

Crane, Lunati, others make good cams. Computer compatible is the key. Just don't fall for the cheap store-brand or stuff non-cam companies like Edelbrock sell.

 

thanks five7...!!

I'll be talking to the machine shop on Monday to get the full picture... damage inside the 305 and options... Charlie (machine shop mechanic) hinted that he had a 350 tpi engine...

If not and I will probably go with the 305... we'll see, but down time and cost are major factors. The 350 block is $300+, replacement electronics are another $150 minumum. I'd like to spend no more than $1500 on the whold rebuild.

heads: do you think polishing and porting are worth the effort? Maybe I should do this myself?

I like your comp cam... sounds about as radical as can be handled with the tpi and computer setup... even saw one on sale on this site.

and i'll probably go for the 1.94 intake valves... hoping it's not too much extra.

 

i have also heard of just pumping up the fuel press of the 5.0 to make it work w the 5.7. I have a 50k 5.7l tpi out of my 92z im trying to get rid of but im in the houston area, how about you. Also you could go to autozone and get a crate motor with a warranty

 

It's not so much bumping up the fuel pressure, it's the size of the injectors themselves. You could easily get the L98 to idle/run on LB9 injectors, but for all out high RPM performance, they're simply not enough....

 

yes they are not enough for high rpm's, but 99% of street cars run below 3 grand most of the time and this way the motor is replaced with more cubes and running and the rest can be upgraded at a later time

 

^ Re-read his initial thread, especially the part regarding the 300+HP he's looking to obtain, then ask yourself if he's one of the 99% that your referring to....

Yes he can upgrade later on, but exactly how long do you think he'll be able to drive his car under 3000-RPM for?

 

the last guy is right... i might exceed 3K during the breakin period...!!

I've made my decision... sticking with stock set-up...

saw the engine open today... kinda bad...

good news is that the heads have 1.94 valves, so I'll stick with them... nice comp xe... that's about it... might go with a nice torque converter... installation is free at this point...

 

if it TPI it stops breathing at 4,800 rpm stock anyway, unless it upgraded? base plate runners tb all ported with alot better heads

 

So...how much rwhp ae you expecting? I saw above you mentioned you were gonna go with the stock setup..the 250hp was that at the wheels or the crank?

 

stock it was 190hp. i've read on this site that the rating was not at the wheels...

i'm planning on putting it on dyno, but only after complete breaking 3,500+ miles... and I'll post the numbers. Nice comp cam, injectors cleaned, 2500 stall hughes t converter, headers.... should be nice....

 

update...

since i can't sleep because the car will be ready tomorrow... i'll take a few and fill you guys in...

yes, I rebuilt the 305... (a respectful silence from the peanut gallary)... The original guts were pretty good... kept the flat top style, upgraded to double timing chain, comp 256 cam, heads were already at 1.94", rebuilt... wished for polish/ported but didn't get it, cleaned and flushed injectors, hughes 2500 stall conveter, edelbrock headers with 3" exhuast... that's it.

so, after about six weeks, it should be ready tomorrow. it's been long and painful... When I bought the car, I planned a methodical 350 conversion, at about 160K, but that bad little motor had different plans.

Ultimate no, but it will run pretty damn sweet... $1,700 for the rebuild, $375 for the tc, $1,300 for R&R... plus tax... plus the recent cost of the exhuast system... $1,200, I think... ouch, ouch and double ouch...

no one is question my love, i hope!!

during the break in, I'll get straight on doing my own tuning or putting in the proper hypertech (jeers and sneers...)

thanks for all the tips... after 3,500 miles or so, planning to stick it on a dyno and taking to the 1/4" track... i'll post the numbers... 260rwhp, 320 torque, 13.75 sec qm... ??