Deadworm

So i fear the 305 tpi is on its way out sooner than later. I want to buy a crate engine in the $2000 price range. My question is what is the best engine for the most direct swap. Im Not the most mechanic incline person but i have some help and plenty of time. Is it easier to go carb or stay tpi? Im not looking for crazy horse power just something to cruise around with. Can anyone post an engine that will drop right in bolt up and with little screwing around will start and run. I know tpi is much more efficent but theres a lot more electronics and things to try and get right so im leaning towards carb. Either way i look at summkt racing and its overwelming theres so many options many dont say if it is tpi compatible. Njst looking for some advice from you guys with the smarts thanks.

Drew

iTrader: (58)

What year car is it going in? 85 would be 2pc rear mainseal, 86 1pc rear main seal, 87-up are 1pc with different intake bolt angles. Any 350 swap, you'll want to change the computer chip, injectors, and knock sensor hardware to cooperate best with the engine.

Sticking with GM crates, 85 or 86 would match up fairly well with the El-Cheapo Goodwrench 350. Probably need a flywheel, but the rest should work alright. 87-up the L05 TBI truck replacement would be a fairly close match. Neither of the above are that performance oriented. The smogger truck heads on the Goodwrench 350, and the swirl ports on the TBI 350 are real turn offs...

The L31 Vortec crate engine would have more benefits, but would require a Vortec TPI base manifold to bolt up to the heads, and may involve some other tinkering. Probably would need to run headers... In my opinion it'd be worth the added work and a little more money for the increase in power.

I'd skip the carb conversion. Personally I've never experienced one first hand that drove well. Not to say it can't be done, but people who go that route usually don't take the time to do the job right.

Sabenott

if you go 2 pc rear main then for a few hundred more this is your best bang for your money
Chevrolet Performance 12499529

Less than $2400 shipped

Drew

iTrader: (58)

I haven't compared every part number, but 12499529 sure looks like 10067353 with an upgraded camshaft. A basic flat tappet camshaft is a $100 upgrade. Even buying the GM cam in the 529, it's under $200, and the 529 is nearly $900 more expensive. Still with 8.5:1 compression, and boat anchor heads.

The 12530283 L31 adds Vortec heads, 9.4:1 compression ratio, hypereutectic pistons, 1pc rms, and a roller cam. Shop around they can be had for around $2000. Pop in a better cam, spend the $400 on an intake (http://sdparts.com/i-23896057-sdpc-s...baseplate.html) and you're HP, and 20+ years ahead of the base engine in technology.

Deadworm

Thanks guys sorry i forgot to mention its an 89 iroc z with 305 tpi engine. I dont mine spending like 2500 bucks to be honest i just want the least amount of head aches dropping in the engine. Will i have issues with sensors if i run with tpi? Can i also use my intake and mount kt on the top of a 350 crate and buy larger fuel injectors? Sorry for tbe qjestions but you guys have so much knowledge and i have read many threads but csnt seem to understand some of the lingo

Sabenott

Yes the sensors will all fit. If you get vortec heads your intake won't fit. 1989 in my opinion has the best tpi setup due to the fact they got rid of the 9th injector and the computer was upgraded to 256k. Also the MAF has more precise metering than the speed density version. I would keep it. Yes injectors will have to be upgraded. I believe the 305 had 19lb/h while the 350 used 21lb/h.

Deadworm

It says the 12499258 is not used with oem fuel injection?. So i decided i woukd keep the tpi set up so we arr moving in the right direction. Whats the best engine to drop in and use my plug in sensors also i will need tuning correct? Should i get a tpi from the junk yard and drop it in jjst want this to go smooth. Hate to drop a crate engine in and not get it to run

Sabenott

Cam may be why. You may try looking on Craigslist for a wrecked tpi car with good motor. Something you can hear before you buy. Tuning will only be needed for maximum performance. For cruising it won't be a problem.

Tuned Performance

iTrader: (92)

Why wouldn't you want to tune ? A 305 calibration running 22#hr injectors is going to run rich.

Sabenott

If you're going to be running wide open throttle yes you will need a tune. Otherwise the computer will be adjusting the AFR. Wot is where the computer runs on a set parameter. So for cruising you don't need one. For running it yes you will. We are not talking a built engine with every bolt on mod.

Tuned Performance

iTrader: (92)

I agree to disagree, to each his real world philosophy.

Dartht33bagger

I did a similar swap last year. 91 Z28 with 305 TPI to a 350 TPI. I went with the L31-R crate motor and did not make any upgrades to it. That set me back $2000. To get the L31-R motor work you need a few things:

1. $400 intake manifold from Scoggy Dickens posted above. You need the TPI to Vortec head intake manifold.
2. Dyno Don headers. They look great and perform great. Worth the money.
3. EBL P4 from http://www.dynamicefi.com/. This replaces the original computer with a better one that you can tune yourself. Since your car is an 89, you will need the EBL Flash most likely (the P4 is for speed density cars). You do need to change the tune with the new motor.
4. 22lb fuel injectors. The stock ones are too small.

Beyond that there are just a few things you'll have to look out for.

1. Vortec heads don't allow for EGR, so you'll have to go without EGR (which shouldn't be a problem unless you have emissions concerns). Charcoal Canister and AIR is still possible to run (I did).
2. The L31 does not have an internal coolant bypass like the previous SBCs did, so you will need to route a line from the intake to the waterpump (simple). The instructions that come with the intake manifold will explain this.
3. The coil bracket will need to be modified to fit in its original location. Everything else is pretty much plug and play from the original motor.
4. Because the stock L31 is pretty close to the vortec tune that comes with the EBL, you don't really have to do too much tuning to get the computer back in line.
5. There is a cam position sensor hole in the bottom of the timing cover on the L31. Since we don't have a cam position sensor, you need to plug this hole. I ended up just buying a new timing cover from Advanced Auto. It came with a screw in plug for the hole. I put the plug on my car and have an extra timing cover laying around. $25 was all it cost.

In total my build set me back about $6k. That was for a new motor, headers, catback exhaust, flywheel, motor mounts, transmission mount, gaskets, and a transmission rebuild.

Deadworm

Thanks darth for the reply . To be honest I think keeping the tpi may just end up costing me more money and more head aches. I drive the car only in the summer and I know carbs require tuning depending on the weather. It's also not my daily driver. It's an 89 305 tpi that will need an engine sooner than later. Just seems easier to swap to carb less wiring headaches ,computer tuning.(it's hard to find people to tune these cars now a day) much easier to find crates that you can slap a carb on and call it a day. Is there any crate engine in particular that I can drop in hook up the tranny, run some wiring and call it a day. In other works what's my best bang for my buck. Crate engine+ carb for around 2-3k what you guys think. Doesn't need to run NASCAR times just something reliable with decent hp

Galaxie500XL

iTrader: (1)

Not intending to steal the thread, but I've been looking at putting an L31 in my 5.7 TPI '88 Camaro.


Regarding the L31, do I recall correctly that there's no timing tab on the timing cover? I'm working out what I need to do in order to be able to set the timing, and this looked like a potential (minor) problem.

Galaxie500XL

iTrader: (1)

Additionally, an L31 with TPI...any idea what sort of gains or losses in terms of horsepower/torque/fuel mileage?

Dartht33bagger

@Galaxie

Timing can suck because the intended way to time the engine is to use the OBD2 computer with the cam position sensor on the trucks. Since we don't have that, we have to get a little more crafty. There is a single tab on the timing cover and a line on the balancer. I turned the engine to where I felt like TDC was and found that the line and the tab lined up. That was 0* timing. Then I used my grandpas adjustable timing light to dial in 6* BTDC, got the balancer lined up with the tab again, and called it good.

An even better way would be to get a piston stop and find TDC exactly. Then you could buy some timing tape and mark off the balancer allowing you to time the engine the old fashioned way. I'm thinking of doing this someday.

Note: The timing cover and the balancer on the L31 is bigger than what came with my 305. So you can't farm the stuff off the old motor.

HP/torque wise I'm not sure. Official documentation says the stock L31-R is 245 HP and 330 ft/lb torque. It definitely feels better than the 305 and is more than enough for me. MPG is around 15 city and 19 highway. Better than my 305 which was 12 city and 15 highway for all of the years I owned it.