danclemts

iTrader: (1)

I must have weak search fu skills. I have a worn out 89 LB9, later this year will be looking for a long block to swap out. I want to keep TPI, either 305 or 350, roller cam is a must. What longblocks and years will swap out? I know I need different injectors and ECU for a 350, thats not a problem. I am willing to fab a new exhaust if a later motor has diff exhaust manifold outlets. Just don't want to get rid of TPI (like the looks). What are my options?

rusty vango

any 87 up 3 fiddy built to your specs/budget will do the job. as always attention to details makes the difference between grenades OR a long lived grin machine. good luck

danclemts

iTrader: (1)

Ok, Finally pulled the heads on my 89 305, got a nice surprise. It still has standard bore pistons in it. I want to rebuild this motor.

I know all the arguments about getting a 350, so please save them for the next guy. The car this motor is in weighs less than a Camaro (85 Volvo). this will be a DD, so fuel economy, 100k plus life and good idle will be priorities

What I do want advice on.. Anybody know of any decent Machine shops in San Antonio Tx.? I also have not built a V8 in over 20 years, what are recommendations for Pistons? My goal for this motor is 250 HP/300lb ft at the crank give or take a few. I rarely spin my motors past 4K. so low end is my goal. I have free flow intake, exhaust, electric cooling system adjustable FPR, nice injectors, roller rockers and a good ignition already
I'll need a cam, roller type.
I'm not sure what I'll do to the heads, guess we'll see how mine look. If they are ok,I'll rebuild them, Recommend springs, retainers.
If for some reason this block can't be used, I'll probably buy whatever I find, 305/350

Damon

Builing a 305 is no different than building a 350, it's just got smaller pistons. You just need a set of 30-over flattop pistons designed for the 305. A set of cast or hypereutectic pistons will work just fine. Stock pistons have a small dish to them but upgrading to flattops is sort of a no-brainer when rebuilding. SpeedPro makes a fine set of hypers for not a lot of bucks.

Cam choice depends on whether you have an automatic trans or manual. 87-90 the 305/auto TPI motors got the itty-bitty "peanut cam" as we call it around here. Very low lift, very small duration. Pure torque cam, nothing left over ~4000 RPMs. The 305/5-speed got the "good guy" cam that's shared with the big brother L98 350 TPI engine. They make factory L98 replacement cams (Check Scoggin Dickey) if you're looking for one to upgrade from a "peanut cam". For your application I doubt you need anything more than that, although there are zillions of different cams available from the aftermarket.

Your cam you can reuse (if it's visually in good shape- they last half of forever) but you might want a set of stock replacement roller lifters to go with it. And I'd put a fresh set of valvesprings in the heads while you have them apart for the rebuild as well. If you want to upgrade from the rather weak stock springs, put a set of Comp 981 springs in as a drop-in upgrade. Obviously, you'll want to replace the timing chain as part of the rebuild as well. GMPP sells a single-roller chain set for factory-style roller cam applications that's cheap and better than you'll ever need it to be.

Good quality machining on the block, crank, rods, and heads. Good quality rings, bearings, fresh gaskets and you're good to go.

rusty vango

finally, someone else who don't subscribe to the dreaded "freefiddy" or worse LS. BS. if you are building a real world driver and you don't give a damn about elapsed times. a well built 305 will provide you with a reliable ,economical happy engine.

danclemts

iTrader: (1)

Damon thanks, I would like a small bump in compression, so flattops will be considered. just wondering I guess about brand of piston maybe. I have a bare bones budget, so if cam is good, I will reuse it, if I replace, it will be a grind with similar specs, maybe just a few degrees, couple of thou lift more. Springs are on the list, as will be lifters and pushrods if cam swapped

Rusty Vango, thanks...It does get old to see "buy a 350" in every 305 info request .....It's not always the answer

Damon

Dan- when you look at replacement pistons beware of some "rebuilder" pistons. Unless you are going to be decking the block a considerable amount, you want to look for pistons with a 1.56" pin height (stock). Some cheapie rebuilder units have a 1.54" pin height, which will put the piston even further down in the hole at TDC. Factory 1.56" pistons on an undecked block will put the piston .025" in the hole at TDC. Using a piston with a 1.54" pin height on an undecked block will put it a massive .045" in the hole. That not only kills your quench height, but also loses you any compression gain you would have had from switching to flattops.

danclemts

iTrader: (1)

thats the kind of info I'm looking for, thanks!