85projectZ28

my engine is acting funny. sputtering and losing power. whatever. i want to rebuild it and need to know about how much i should be expected to pay.

it is a 305 TPI on a 1985 Z28. it has probably 300 or 400 thousand miles on it. just rolled over but only reads to the ten thousands.

i think all it needs is new injectors and plugs on the outside. as for the inside, it feels like its lost a lot of compresion and power. it may just need new piston rings, or it may need to be honed or bored a little bigger and then new pistons as well. other than that im not too sure.

so to have someone take it out, fix it, and put it back in, doing these things... what can i expect to pay for this rebuild?

i would love to do it myself but i literally have no time. if there is any other info that i left out that would help estimate a price, please let me know. but all input is appreciated. thanks guys!

five7kid

iTrader: (14)

Depending upon what they have to do to fix it up, between $1500-$2500.

Guest

It's probably wiser to just find a 100,000 mile 305, do a re-ring kit on it, and save money, or step up to a 350, and get better results from your $1500 investment.

TNT_Z28

PLEASE, PLEASE, PLEASE tell me ur going to upgrade to a 350. i know from experience the benefits over a 305.

1. Unmatched performance. i ran and represented a 305 for two years and ill be the first to tell you they are trash. any money or parts you put into one would yield far greater perfomance in a 350.

2. Exteriorly Identical. you could reuse the sheet metal (oil pan, timing cover, valve covers), rocker arms, and in your case the TPI system. also all the bolt holes are in the same location. 305 to 350 = easiest swap ever.

3. Bang for ur buck. five7 quoted you 1500 - 2500. you can pull a 350 from a junk yard for $50-$100. Take it to a machine shop and spend $700-$900 and have a brand new engine.

you'll probably have to change some sensors. i know the knock sensor for sure has to be changed. but the best part about a new engine is you can assemble the long block on a stand WHILE ur driving your car with the 305.

i know a motor swap sounds intimidating but trust me its not that bad and its highly worth the effort.

KNBlazer

the current engine that I have in my car right now is a 305... I rebuilt it back in 03 or so and have put maybe about 10K miles ... well the only reason I didn't go with a 350 was because I though it would be very difficult to do the swap... well I was wrong it's not as hard as you think... I would rather have gone with a 350 than the 305 I have now... on labor alone including the machine shop fees I spend 900 dollars... on parts I spent about 2000 dollars or so ...

Jim85IROC

iTrader: (2)

Putting a 350 into an 85 TPI car is, in my opinion, more challenging than in an 86+. The 85 computer is primitive, and there's not a lot of tuning support for it, at least from a DIY perspective. My car ran terrible with the stock 85 computer & chip, and I eventually swapped to a 165 ECM.

That said, I'd still take that route again before I ever considered rebuilding a boat anchor 305. In most cases it's cheaper to rebuild a 350 because of the huge amount of product that's available. The money you save on a rebuild kit will pay for the long block.

Saabster

iTrader: (2)

I think his quote was for a general small block rebuild. There's no reason a 305 rebuild would cost more, everything but the piston bore size is exactly the same.

As I always say in these threads, a GM 350 1-pc rear shortblock is ~$1200 and is capable of 5500 rpms. Add $600 worth of vortec heads and a GM LT4 hot cam kit plus a few other odds and ends and you have a 400 hp engine. As you have a non-roller engine you can pick up a whole vortec 350 for $2200, and that'll have the roller lifters.

Bottom line, don't rebuild a 305 unless you're going to do so on the cheap.

GTAman

iTrader: (2)

hey saabster, point me in the direction to where i can get a vortec 350 for $2200? i'll buy it now!

Saabster

iTrader: (2)

Behold, the L31 long block.

five7kid

iTrader: (14)

Actually, it's $2269.95 - "The part NAL-12530283 has an additional core charge of $100.00 per item."

Plus freight. Probably at least $300.

Plus a $400 Vortec base.

A decent deal. But, the OP also indicated he wants someone to do the job. So, probably another $500-$800.

Plus the aforementioned 350-specific parts like injectors and knock sensor.

Still not too bad a deal.

Would probably run better with an '86-up ECM. Make it '87-'89 for L98, and to keep it MAF.

david chambers

IF you do most if not all of the labor and you only pay the machine shop for actual machining of your block you can get by for about $1,200. i too am in the middle of a complete "LB9" 305 rebuild,im shooting for 230hp and 295lb.ft.

david chambers

bottom line,,,,,do not spend say $3000 for a engine there are people who just cant help themselves i guess they say words like "vortec"(wont fit a TPI intake) and "350"(wont work with 305 injectors or the computer) just do only what you HAVE to do to return your engine to good condition and you will be happy AND you wont have spent needless thousands of dollars for little gains

five7kid

iTrader: (14)

1) He stated from the beginning that he would like to rebuild it himself, but doesn't have the time. So, he's willing to pay someone to do it.

2) If you're paying someone, a lot of the little savings that you can realize when doing it yourself don't apply.

3) If you're paying someone to get a rebuilt engine in your car, having a rebuilt long block ready to go in is a smart way to go. Labor for a custom rebuild-my-engine is going to increase the cost substantially.

4) Don't know if it's true, but the OP thinks his injectors need to be replaced. Sounds like a perfect opportunity to go 350.

5) There is a Vortec TPI base available. Pricey, but available.

6) Going from LB9 to L31 w/TPI is not "little gains".

7) MAF 305 computers will work with a 350. The '85 wasn't their best effort, but MAF '86-'89 ECM's aren't that expensive.

five7kid

iTrader: (14)

These guys put out a good product http://www.rebuilt-auto-engines.com/...51110496123.a1 . $1375 plus freight for a well-built, reliable 350. They'll spec the cam based on your install (they actually talk to you when you order and make sure you're getting what will work for you). Have that shipped to the shop that will be doing the install. Let the shop doing the install keep the old 305 long block (eat the core charge - it's cheaper than shipping the core back to them).

Atilla the Fun

Right idea, wrong source. And how can there be a core charge on an all new engine?
the 12530282 can be had from www.sdparts.com or www.gmpartsdirect.com for around $2200.

Saabster

iTrader: (2)

You got me.

Personally if I was going to go to a 350 I'd forget the Vortec long block and get a vortec short block instead. Pop out the pistons and crank. Replace the pistons with SpeedPro flat tops, the rod bolts with ARP hardware, balance the crank, and get ARP bolts for the mains. The bottom end should now be ready to rock and roll to 6000 rpms.

five7kid

iTrader: (14)

Punch that p/n into the gmpartsdirect.com site. You might be surprised at what you see. . .

Atilla the Fun

Why is everyone so eager to have 10.5:1 compression? You don't need to do any of that for a 6000 rpm shift point, nor to get to 400 HP.

Atilla the Fun

Damn! Yes, I am surprised.

85projectZ28

wow guys! lotta good info here! lotta helpful tips too.

Well I am going 350. i have a 350 bored .060" over and decked to 9.005" 3.75" stroker baby as 388 cubes, in my garage. im building that one special! it should have around 520hp. but that ones gunna cost me about 6 -7 grand to build it the way i want.

so in the meantime, i still want to drive my baby around but shes not too reliable now. i just need a basic rebuild to get her running good again. i dont want to spend a lot to do it because i want to put my money into my new engine, tranny, diff, drivetrain, suspension, etc.

to go as frugal as possible, i may just have to find time to do it myself. summit has a rebuild kit for $320.00 ish... my machine shop guy can hone or bore my cyllinders for about 100 and then i will just need to get a good set of injectors and pop it back in. (easy right?) problem is i have never pulled an engine and dont know how.

im sure i can learn, and im going to need to so i can swap my 350 in when its done. i just gotta find the time and the help. but i appreciate all the help with this so far! thanks alot for all the input. and any more is all good with me!

KNBlazer

.060 over? .... that's not too "on the dark side" gray area.... I thought .040 was the most you should go with... .060 isn't it asking for trouble..?

Saabster

iTrader: (2)

Well with a setup like that I'd be looking for 450-470 hp.

MotorMouth

.060 used to be the norm for 383 when you used a 400 crank.

sonjaab

For a dependable daily driver your nuts using a bored out/cammed motor unless you want to be under the hood fooling with it daily!
(I been that route with my GTO and that was a old school tech
bad boy motor!)

Best bet IMO............Call NAPA or other parts house and get a complete longblock L-69 305 for around $1000 bucks.
Then just swap over your intake TPI set up, dist, and other small parts and turn the key and have fun!
No fussing with the computer or other PIA problems if going to a bored out 350 or other combo!

No muss, no fuss and dependable all all get out!
Not to mention its just a non complicated plug n play swap to boot IMO!

five7kid

iTrader: (14)

Let's get back to first principles - what's wrong with what you have now?

Sputtering and power loss could easily be tune up and/or fuel system clean-up. Loss of compression - do a compression test and find out.

It's fair to say that these engines do very well on the lower end. My 304k mile '82 305 still had a hint of cross-hatch in the cylinder walls, and oil pressure was fine.

The heads are a different story. Valve guides wear, valve stem seals harden, valve springs get weak - they quit doing what they were designed to do.

With just a tune-up, injectors, and valve job, you could very well have back a dependable and enjoyable driver.

85projectZ28

[quote=five7kid;4551298]Let's get back to first principles - what's wrong with what you have now?quote]


i dont know, at idle its real choppy and feels like its gunna die. at take off, it putt putt putters into motion until about 20 mph then its ok. at full throttle it ltterally feels like there is no fuel for a second, then it goes for a second, then no fuel again and it does that over and over. it also has blueish smoke, an indication of oil leaking into the cylinders.

85projectZ28

ok good news. i found a 305 out of an 85 chevy on craigslist for 200 obo! i think im just going to get that, take it to my machine shop guy, and then swap my parts and replace any bad ones. shouldnt be more than $700 all together right? just gotta learn how to pull and install one. whatcha think?