New member here, been a lurker for a while and read LOTS of good info.

Anyway, we have a 91 Z28 with the 5.0 TPI. She runs OK, but not without issues. I wouldn't go more than an hour or so away. So, thinking it's time to... UPGRADE!

I'm limited to a $4K budget. Wondering what you guys think about the following options...

1) Buy used 5.7 TPI w/ harness & ecm from Hawks. Deliver to local machine shop, have rebuilt. Should be about $3000 all together, 1500 + 1500 for rebuild.

2) Go with a budget crate motor, carbed at my budget I'm guessing.

3) Buy used 5.7 and rebuild myself.

Any other bright ideas? Looking to get this ball rolling in the next 30 days. I have a nice shiny new 2T engine hoist, etc sitting in my garage begging to be used... I will do the remove and install myself, but building the engine myself? Not so confident.

 

Can you find a local 350 block, latemodel roller setup like stock, and have a local shop rebuild you a budget shortblock and then do the assembly of the heads/cam/rest of the motor yourself? Fairly easy to do with some instructional books/videos and an already assembled shortblock.

Likely be the cheapest bet.

 

Not thrilled with the term crate engines given the range of quality crate engines that are available these days.Some bottom dollar stuff is real junk.Consider the following:

If you buy a crate engine most come with some sort of guarantee.But that is only replacement of the engine and not shipping,labor to swap it out or parts.

If you have built a engine,most are not in high performance engines guaranteed unless you go with higher dollar sources.But atleast you have a chance to involve yourself in what exactly is built.

The L31's are roller engines 96 and up and are a cheap not too bad start for a rebuild that you could mold into what you want.

 

hey bud...do what i did...go to summit / jegs...get the gmpp 350 /290hp which from summit with carb, edelbrock intake, headers, msd, k&n he says i have 325hp est...comes all brand new with year warranty and corvette cam...sounds great...so far been pleased....4bolt main...never been machined...so gots lots of life for furture upgrades...etc

 

Not a very good idea in his case. It would be an upgrade to an '82 LG4, but not a '91 LB9. Poor heads, low compression, flat tappet cam, '85-earlier intake bolt pattern, perimeter bolt valve cover, 2-piece rear main seal - all downgrades from the LB9.

I agree with 1gary - get a '96-'99 L31 350 from a light truck and rebuild it. Only issues I know with them involve rod bearings, so make sure you use good bearings and a new oil pump when you rebuild it. You will need a Vortec-type TPI base, but this is also an opportunity to upgrade the TPI (the Holley/Weiand Stealth Ram is available in Vortec configuration, and is a reasonably-priced piece).

Another alternative would be to get a generic '87-up 350 shortblock with roller lifter provisions (some truck 350's had the provisions but flat tappet cam), rebuild the shortblock, then put your 305 cam/lifters, heads & TPI in/on it.

 

I like the idea of the L31. I can get an L31 long from Jegs for 2K (http://www.jegs.com/i/GM-Performance...ductId=1532025#). Add to that the Holley/Weiand stealth ram setup for what, $800? (http://www.holley.com/7542P.asp). I can reuse about everything accessory wise off the 305.... what about exaust? Won't the factory exaust/manifolds be pretty anemic?

Anyone, just the L31 LB from Jegs and the stealth ram is 2800, other concerns? What should I be looking at here... Can I retain my ECM and just have a new prom burned for this? And will need higher cap injectors? Probably want a different cam...

 

A little less on summitracing.com. A lot less if you don't go with the polished version.

If you have the dual cat exhaust, it isn't too bad. But, headers would be better, of course. If you have dual cats, Hedman makes dual cat headers that are pretty decent. If you have single cat, you'll want to replace the entire exhaust system.

You will have to tune the computer for the 350. The factory used 19 lb injectors for 305, 22 lb injectors for 350. The 305 injectors will be fine except at full power (depending upon cam & exhaust you end up with).

I don't know the L31 cam specs off the top of my head, but I believe it is close to the LB9. Certainly an aftermarket cam would be better. Just watch the lift, as Vortec heads are lift-limited (unless modified).

 

OK so lets see...

L31-R from Jegs, $1980
Weiand 7452 StealthRam from Summit, $370
Summit headers, $140
Header back exhaust kit, $360
Keep the 'stock' cam for now, see how it goes.

What am I missing? I'm only at $2850, so I must be missing tons of stuff, LOL.

 

Alright...

Been doing a LOT of research on cams, particularly in Vortec applications. I have decided (correctly I hope) that the following grind should produce a good balance of performance and streetability and be well withing the limits of the Vortec head limited lift.

lift .479/.518
duration .050" 210/224
lsa 112

Some of you guys are gurus compared to my limited knowledge, so just looking for opinions I guess. Again, looking for a good DD/performance compromise (and yes, I will replace the springs too!).

 

Reconsider your exhaust choices. Summit headers are made by Flowtech, cheap, 1-1/2" primaries. Not sure what "header back" kit you're looking at, but I'd guess it's a universal kit and not well suited to 3rd gens.

Do you have single or dual cat? If dual cat, the Hedman headers I mentioned are a good choice. If single cat, then consider Hooker 2055HKR headers & y-pipe, a direct-fit cat such as a Catco 9118, and a cat-back of your choice for the '86-'90 TPI single cat application.

That cam has a lot of lift for the duration. Is it roller lifter or flat tappet?

 

Actually, I'm heavily considering ordering from Dyno Don for the headers. Then take it in and have a pro do the cat back.

The cam is a flat tappet. I'm doing a lot of hemming and hawing on the cam anyway.... If I cam it, I need to change the springs, which really means I should have the heads machined and the studs replaced with screw in. If I do that, why not open them up for more lift... and that's $$. I'm on a budget. The L31 'stock', with the Stealth Ram, 22-24# injectors, and a good exhaust, should make me happy by itself for a bit... being I'm used to the 305. So I don't know, maybe I'll toss the money into what I HAVE to change, get quality, and take my time on the cam?

Changing out a motor is easy. Deciding what to do with it, that's the tough part!

 

Dyno Don headers would be a good choice, from all I've heard. He'll make them to bolt up to an aftermarket cat-back system that you can bolt in yourself. No need to waste precious performance $'s on someone reinventing the wheel and charging specialist labor rates for what you can buy and do yourself.

Machining the Vortec heads for more lift and better springs is a good investment without any other work on the heads. If you do have some porting work done, though, have them leave the intakes alone - not much to be gained there. For the exhaust, 1.60" valves and a little clean-up will make them much better than what you have now. They are pretty good heads without needing much done to them.

 

OK.... Ordered the engine, stealth ram, fuel rails,24# injectors, purtier valve covers (lol), headers and Y pipe earlier this week. All but the engine should be here today, the engine ships tomorrow. From Jegs. Total cost, $3K. Not too bad, the free shipping on GM engines helped. So far I am well under budget. Got my Moates G1 adapter yesterday, and my new prom should be here next week.

Now, I just realized the Hedman 68470 headers and 17470 Y pipe have no O2 provision... Oopsy. A 3" to 2 1/4" reducer w/ O2 bung should work, as I am running stock cat back for now, correct? The rest of the exaust will be updated in a few months... I'm doing this in stages to focus my budget on a nice purty vroom vroom engine for now... then in June, exhaust cat back is being replaced, and in August, redoing the entire suspension and a 'new' 700R4. Maybe summer 2013, interior redone and a good blocking and paint for the bod.

But I digress... the reducer... stock is 2 1/4" to the cat, correct?

 

sounds like you got it all figured out

 

Thanks!

I didn't want to order a 3 to 2.25 and wind up needing a 3 to 2.5, LOL. Wouldn't be the first time ordering the wrong part...

 

Why not have the O2 bung welded onto the driver side collector? No need for extra parts other than the $6 bung. Not hard to weld in with a wire or MIG welder.

I really don't like that Hedman Y-pipe. You see that 2-1/2"-3" reducer they include? That's to connect the 2-1/2" Y-pipe outlet to your 3" cat inlet. YUCK! "Fixing" that pipe is going to be expensive. Leave it like it is, and it will be a permanent restriction to power. Personally, the only viable choices I see are 2055's headers, Hedman dual-cat headers, or Dyno Don's headers.

But, it's your money and your car, so I'll zip up now.

 

I don't weld... Well, I can, but not well. So it's either $30 for the reducer, or a $60 bung and the cost of the welder, or a $6 bung and pay someone to do it... I'll just order the reducer, LOL. Not being picky about the exhaust for now, she should be just fine with this exhaust setup until I improve the heads and cam. That's several months or more down the road. The old 305 in there is so tired a fresh 6 banger would be an improvement....

Anyway, got everything I ordered, including the Moates G1 and my ne eprom, sitting here except the engine... it's on it's way and should be here later this week. I stripped the headers (factory coat on those is not heat resistant) and used Rustoleum 2K degree primer and flat black 2K paint. They look nice. The block comes in black paint, so I bought tall aluminum valve covers in black with the red Chevy logo on them, and primed and painted a new water pump I had sitting around. I plan on having everything under the hood either black, red, or satin aluminum. Gonna be a LOT of painting, I can't afford all anodized billet right now....

Anyone used those billet one piece wire looms that mount to the valve cover bolts? I'm thinking they'll look rather nice, but haven't actually seen them in use.

I've been giddy to get the car into the garage and start deconstucting ever since I recieved the first of my stuff Fedex. But, since it's my wife's DD right now, I can't allow myself to do so until I have the new motor prepped and ready to drop in to minimize garage time. Can't believe how excited I am about this though. Great feeling.

In the end, I'm having so much fun with this I'm thinking of getting a gen 2 or gen 3 for myself just to build for fun. Then, I won't have to restrict work time as it'll be a third vehicle.

 

Just because I don't have the actual motor in the garage yet doesn't mean I can't post pics... :-)

 

Agreed! I have that Hedman Y pipe, When I bought it I didn't pay attention to the 2 1/2 outlet. A friend of mine works at a exhaust fabrication shop so he made a 3 inch mandrel bent pipe for it, we just cut where the 2 pipes merge and welded up the new pipe, haven't drove it with the new pipe because the car is winterized, kinda doubt it will make a big difference but I feel better about it. The headers are great and the plugs are very easy to get to. good luck.

Mark.

 

Does anyone know if a kit is available that contains the various fittings (vacuum fittings, coolant) for the manifold port? I know I can reuse the ones off my stock manifold, but they look pretty crappy. I'd like to get new ones and not have to buy them piecemeal.

 

Well, everything is ready and I'll be dropping the new motor in tomorrow. Wish me luck. I'm going to try to have it back on the road tomorrow night.

 

I have the same headers on my 87, When you go to drop it in they will rub on the pass. A arm so you'll have to finagle with it a bit. Then when all is said and done and in the bay they will continue to rub on A arm. I just hooked one end of header to a ratchet strap and other to a car then clicked enough until I was satisfied with clearance.