Hi,
Im kind of new around here and have a few questions about a LT1 Cam swap and porting my heads.First I have a 1991 Camaro RS with a 305 tbi equipped with flowmaster exhaust,hypertech chip and open element air filter.I used the search button and found some information but none answered my questions.

First off,here is my dilemma.The previous owner of my camaro broke 2 rear most exhaust studs on the drivers side head and had an annoying exhaust leak.So I tried tapping it out but couldnt because it was too crowded.So I took off the head and tapped out the broken studs.Now that i have the intake and heads off,i took off the water pump to change the timing chain because it has 120K.

So,i figure while im at it, i should see if i can do minor mods to the engine since we all know the LO3 needs some help.So after browsing i can get a lt1 cam under 30 bux.Now my questions.Do i have to change my valve springs?Also can i use my stock timing chain and lifters?Any adjustments to the computer?This is a daily cruiser so im not looking for major gains,just to add a lil bit of performance.Also what kind of idle will it have and should i expect any problems when i install it?If possible are there any links out there...Also how do i know how much to grind off the dowel pin...Sorry for all the questions =I

As for the porting question,since i have the heads off,should i port the heads and intake manifolds?If so any things i should bring into perspective....Money is a major thing so i cannot bring it to the shop but i do have all the tools needed.Thank you in advance

 

I am in the same situation as you are. I am only reusing the stock valve springs with my LT1 cam swap becuase they only have 35,000 origonal miles. I really should not do this but this motor is a learning project and I do not expect this motor to last more than another year (major plans for the car). I am pretty much only going to be moving this car from shop to shop for body work and what not while I build her up. So at most I may put a hundred miles or so on the reused parts. In additon I am going with a LT1 cam out of a 96 SS impala and it is a tad smaller all around than the LT1 cam found in f bods and vettes. With your 120,000 mile car you NEED to replace the springs and timing chain because they are worn. I am even going to replace my timing chain even though it has so little miles on it. You really need to computer tune any cam swap becuase the stock tune is so bad. The car will run with some more base timing and an adjustable fuel pressure regulator but i do not recomend it. My buddies LT1 cam swap was HORRENDOUS with the stock tune until he learned how to tune properly. In fact, his car was slower than it was with the stock cam. You can reuse the stock lifters and pushrods. You should replace the valve seals and locks while you are in there though. That is what i am doing as I type this. But all in all you can do this swap for cheap. I say $150 for gaskets, locks, springs and chain. Give or take $30 that is.

 

If you have the stock gears in the rear end, and you dont have a way of tuning the computer, then dont swap the cam. I learned the hard way, but all is well now

 

yip i just got done with having my heads rebuilt, you can get away with it really cheap if you do it yourself, but if you send them off to have em done your better off buying new heads and getting some better flow characteristics out of the box. headset gaskets arent as cheap as i thought they were but with a blown head gasket i had no choice. I forgot i had to tune the computer since i did cam swap & all.

 

I pretty much did what your talking about - I went a little further. I have a '90 305 TBI LO3 auto.

I home ported/polished #416 heads from an '85 LG4. Used electric die grinder and carbide cutting bits. Had machine shop do valve job, replace seals, and cut intakes for 1.94 valves, installed Manley racing valves, left exhaust valves at 1.5, new springs. I put in new pushrods (just to cover my butt), but used same size, reused lifters. Heads $100. Shop charged $225. Grinder and bits $85. Valves $75, Springs $50, Pushrods $50. I added 1.6:1 roller-tip rockers, $100.

Installed used LT1 cam, $40. Lift .480/.490 with the 1.6:1 rockers.

Put in Weiand Action Plus carb intake manifold, $125. TBI adapter for carb intake, $35, and EGR adapter to clear TBI, $60.

VaFPR on TBI from TDS, $85. Double roller timing chain, $50.

Hedman Smog-legal Headers, $315. Coated them myself in an old oven with ceramic sprays, $25.

I lucked across a posi rear, 3.08 gears, for $125 complete. Not great gears, but much better. Swapped rears in a weekend, installed new shocks $50, rear springs $75, larger front and rear sway bars $75, TDS steering brace ("wonderbar") $50, poly sway bushings $75 frt & rear, and all new drum brake components $65.

Got an extra air cleaner housing for $10, made a homemade dual snorkel for $25 total with flexible hosing from Advance Auto. Relocated heater diverter valve and coolant bottle for second snorkel clearance.

All gaskets replaced and replaced again, vacuum hosing, heater hoses to reroute for mods, etc, so on, so forth, add another $150 for "misc."

I started all this work in June '03. Took me 3 months - only had weekends, and evenings to "tinker".

Now, 6 months later, and a lot of cash spent, car doesn't run well at all. Too much airflow means Very Very rich at idle. Currently getting chips programmed, a long tedious process since I must rely on someone else for the programming.

Final words - I am by no means disappointed! I had a blast tinkering, and I had to spend my money some where right? I learned tons, entertained myself plenty, and learned just how greasy one can get. I got the bug, and kept going and going. I introduced way too much breathing with headers, ported heads, larger rockers, and larger intake valve - and thus the necessity for major chip tuning.

With an LO3 engine, as the song goes, "One thing leads to another". Intake Mani no good without cam. Cam no good without heads. None of it good without headers. But I'll have it running soon, one way or another. And after all is done, it still probably won't beat a 1995 Nissan Quest minivan (they really fly!)

However..... the lesson learned is that:

A), everything costs way more than you estimate - double what you think, and then add 20% - NO MATTER WHAT YOU THINK, YOU'LL SPEND AT LEAST THAT MUCH - no one is tighter than I, and I spent double what I originally thought +20% at least.

B), use the formula in lesson A to estimate time as well... a.k.a. - HAVE ALTERNATE LONG-TERM MEANS OF TRANSPORTATION!

C), given lesson A & B, you really could have done the same to a 350 for about the same $/time.

D), as with anything in life, it's all relative - relative to what you have, what you can do, what you can spend, what time you have, and what makes you happy.

Things that can be done to LO3 without major chip tuning:
- Homemade Dual Snorkel - made a definite SOTP difference
- Posi rear with better gears - an really nice SOTP difference
- New shocks, rear springs, bushings, sway bars
- Ultimate TBI mods
- Maybe Headers
- Maybe LT1 cam without head changes, valvetrain changes
- Maybe NOT LT1 cam and headers both

Anyone feel free to PM me for specifics on anything - as you can tell I'm happy to ramble about my ride

 

I did forget to mention - don't even consider porting the stock LO3 heads - those heads are useless for anything short of a boat anchor.

 

Agreed. When i did my cam swap O had a pretty close look into them. I was going to port them only for practice and if I messed up, oh well. Upon further review there is just to much to port and I think it would take 49574875 years and leave the head with no strength left.