I am mainly going to freshen up my block. I wanted to ask about replacing the pistons. I found some new not too expensive stock replacements. Would it be a good idea to go ahead and replace them? Engine only has 96,000 miles but has been sitting for about 4 years and as of right now I have not tore down the block to see the pistons.

Also, the engine is the 87 TPI 305 with a T5 which got the better cam. Could I "cheat" and change over to 1.6 lifters to get a little more power for the stock cam? I'm not looking to race or even spend that much on this 305. What will increasing the lifter size do for torque and over all HP? I'm so new at this that most of what I read was Greek to me. Any help and suggestions on a simple rebuild/freshen up would be very helpful.

Thanks,
Tommy

 

No.

Why would you want to do that, when a 350 block is as cheap as $50, and pistons are the same cost OR CHEAPER? Think about it.... it MIGHT actually cost you LESS to BUY another core to rebuild, by the time you're done with the project, than to build the "free" "paid for" core you've got. And even BETTER, that other core will give you more bang for every buck you put into it.

 

 

Well im just wondering does it make a difference if the block is not a rollor?

B/c I can get a 4- bolt main block, But it is not a rollor? Is that gonna be a big difference ? I can just get it dirt cheap and I was wondering if that would a good idea?

I would be running a TPI setup on it.

( sry not to steal the thread I was j/w.)

 

What makes you think that you need to tear the engine apart? These 305's will go 200+ K miles without a rebuild.

If the car has been sitting for 4 years you should replace the battery, put some fresh fuel in it, change the oil & filter, air filter, check the coolant level and see if it will start. Next consider installing new spark plugs, plug wires, dist cap & rotor. New exhaust is next, consider headers too. Some folks do like 1.6 rockers. I went with 1.52 steel roller tips and am happy with them. Changing rocker ratio does little to increase power on a 305, maybe 5HP.

 

I know one side was knocking pretty bad. That is why I parked it and slowly started "restoring" it. I have all but pulled the engine/tranny out, so i figured while it was out might as well freshen it up since I have no idea how hard it was run before I got it. I already have headers and back exhaust for it and bigger runners/throttle body/and slightly ported stock intake. Also going to improve the ignition/injectors and maybe a adj. fuel regulator. It's an 87 Iroc vert so I want to at least keep the original block, trans and rear end. I'll hotrod a not so rare camaro in the future

Only 5 hp with the 1.6 rockers huh? any suggestions on aftermarket cam that will increase low to midrange power and not kill my MPG?

 

NOBODY cares about an "original" block in that kind of car, if it's a 305.

If you're really worried about it, stash it off in some forgotten corner of your garage, and pass it along to the next owner of the car .... if they care enough to be bothered taking it with them.

Don't waste your own money on it.

 

If that car is a "Factory Convertible" it is very rare indeed. In 1987 there were only 744 of them built, and most were automatic transmissions. I would guess that there were only 200 or so built with the T5.

I would keep the block, in fact if the cylinders look good I'd may even pass on boreing it. My car has 150 K miles on it, and there was no ridge ring that I could feel. With only 96 K miles your cylinders may be in even better shape than mine are. You may be able to just hone and re-ring it.

Did you do a compression test yet? My engine checked out at 161 psi +\- 3.5%. If yours checks out as well I'd say you may want to re-think this...

 

The stock cam in that engine is a pretty good cam for low end power, still a little more lift would be good, so 1.6 rockers may be all that you want to do.

The deal with cams is that the longer the duration, the higher in RPM the power peak occurs. So if you go with a longer duration cam, your power band will move up. TPI builds power down low, so too much duration will be a poor match for your intake.

Lift is a different issue, increasing lift will not move the power band. However, the stock heads will only acommodate lifts to ~.480 or less before you run into spring bind. And they need to be ported in order to flow well. You could get them machined to allow more lift, but then you would also want to port them, change to screw in rocker studs, and 1.94 intake valves. Basically working over the stock heads will result in a good set of heads, but it's expensive. I decided to put the stock heads in the corner of my garage and get a new set of heads that already had all the features that I was looking for. The end result price tag isn't much more than working over the stock heads.

There are several cams that work well for your engine. The Crane cam that I have is about as big in duration as you'd want to go, and it will move the power band up ~ 500 RPM. Still you will get a power increase on the low end/mid as well. Crane makes the 2032 p/n 104224 (which I have). Comp makes the XR264HR which is similar to the Crane cam but has a touch less duration, and a little more lift. These are about as big as you should go with a Computer Controlled TPI engine. A few degrees less duration would be fine too.

In a nut shell, lifts of .450 to .510 are good. Durations @ .050 of 208 to 220 are good. LSA's of 112 to 115 deg. are good. Split pattern cam's are the most popular (i.e. the Crane 2032 @ .050 is 214/220 durations & 452/465 lifts.)

Your stock cam is: Cam: 404/415 202/207 114.5 deg. Hyd. Roller GM Part #14093643.