Weffy

I have a 85' IROC - 305 LB9 on its last wimb here, and I was looking around and I don't see much about building them, or swapping them. I don't have a lot of cash, and I want a fresh motor. Now, should I rebuild this 305 to spec, or build a different motor?
The trans is, I think, a 700r4, getting rebuilt also.

I don't have any experience with engines pretty much, and this will be the first time I've ever pulled one. I've read a lot but theres still so much that I have no clue about, like how tbi works at all, or how to correctly adjust the timing.

1981LT1

iTrader: (1)

It all depends on how much you have to spend. You can get a really good crate motor (long block) for very little cash, or you can do basic freshen up of your engine with new bearings, rings, seals, etc. Since your car is tbi, the computer will control almost all of the functions. You will have to set the base timing but there are ALOT of articles on how to do that.

wildjyoung

iTrader: (6)

Most people are going to tell you that if you want power it is best to rebuild a 350. The cost is almost exactly the same as building a 305. However, if you are on a limited budget and cannot find a good block just rebuild your 305. I have heard that Summit Racing sells "ready to build" 350 blocks for around $650 delivered. This is much less that buying a new block and having the machining and reconditioning done. If you do not mind me asking, what is your budget?

As far as rebuilding yourself, you will most likely have no problems if you have mechanical aptitude. However, I would highly reccomend that you find a friend or professional who has done it before to watch you so that nothing is forgotten. I paid a guy $200 to come and help me for 8 hours and learned a lot. It was cheap insurance and I now feel confident building any motor going forward.

Weffy

Ok, so if I decide to just 'freshen up' my 305, what would I need to do besides the following?
-Rebuild Kit from summit (gaskets, pistons, rings, bearings, plugs, seals.)
-Block decked,mains honed, bore cylinders
-valve seats

Thats all that I can think of, I know I'm missing things, please tell me. This engine has bad knock too. I just want to know what I'm getting myself into.

Weffy

I have $1400 for now to put into the car. 500 of that is for the transmission, so about 8-900

Yeah, I'm on a tight budget.

I know my buddy rebuilt his ford, and he will be helping me along the way, and I have a tendency for perfection and to double check everything twice.

five7kid

iTrader: (14)

What exactly is wrong with your 305?

$500 is do-it-yourself money for a TH700. Or a torque converter.

Honing mains is rarely needed. Decking the block is a little more common, but not necessary unless the deck really is warped. Boring the cylinders and new pistons only needed if bore wear or taper is excessive (you might find the cylinders are fine).

$50 builder shortblock 350's aren't all that uncommon. Doesn't have to be a car engine, doesn't even have to be '85 ('88-'95 truck 350 engines are fairly plentiful and make a good base to build from). The substantial difference between a 305 and 350 performance-wise really makes the minimal difference in cost getting a 350 shortblock inconsequential - especially when you're on a budget.

My advice is to not spend a dime on a 305 shortblock beyond rings, bearings, and oil pump. If it needs to go to a machine shop for anything more than tanking, just get a 350.

305 heads are worth rebuilding, even for a 350.

Weffy

Ok so I'll be on the lookout for a 350 block on the cheap. For now I'm gonna tear down the engine and just put the rebuild kit with no pistons and a new oil pump. I'll rebuild the heads good since they can go on a 350 and perform well.

The thing is if the rods are knocking on my 305 doesn't that most likely mean that I'll have to get the crank done? And, what could have caused the knocking in the first place? Just bad maintenance? I checked the oil and it looks pretty bad, thick and black. I peeked in the valve cover and it looked like a gooey mess from what I could see, but not too bad.

I got a quote from a local transmission shop to rebuild the 700 for $450, I don't think that was including anything about the torque converter except for testing it. There are some reviews online about the place, and half were great and half said their transmission died or the like, so I'm not too sure.

five7kid

iTrader: (14)

Okay, more information is good.

Rod knocking and goo under the valve covers is a pretty good indication that a full rebuild is in order. Time to get serious about finding a 350. A couple of years ago I had a complete 305 that ran fine that I would have given you. Oh, well.

$450 for a TH700 rebuild would lead me to believe the 2nd half of the customer feedback. $1000 is more typical, $1500 not unusual if removed and installed by the shop.

Weffy

Man, that would have been nice.

I guess I'll know for sure what to do with this 305 once I get it out this weekend. Maybe I can find a running one with low miles around here that someones selling for cheap.

But $1000 seems a little steep, I see rebuilt transmissions on ebay with 3 year warranties for about 750 with no core charge. I figured 500 was reasonable since theres no core, and no shipping.

Maybe he would have just stuck a bunch of other charges on me.

Weffy

I'm also unsure of how to put an engine in a car that didn't come out of it. Would everything line up? If i put a 350 in

five7kid

iTrader: (14)

The only external differences between small block Chevys involve the year model. For instance, '79-earlier had the dipstick on the driver side (makes using stock exhaust manifolds very difficult). '86-up had one-piece rear main seal (different oil pan, which should come with the new engine, and different flex plate, which is pretty cheap to buy new). There were also differences in the timing tab on the front cover, but that's just a matter of matching the cover and damper (if you use what came with the 350, no problem - your 305 pulleys will bolt up to any SBC damper). Some really, really old 350's didn't have the proper starter mount bolt holes drilled & tapped.

Other than that, the differences are in the heads; and if you use your existing 305 heads, that becomes moot.

Weffy

Wow that was informative. I really want a 350 now.
What about the tpi system? Will it still function or will it have to be reprogrammed somehow?

five7kid

iTrader: (14)

It will function fine as long as the sensors are all there, and the cam is appropriate.

You could make it better. 350 TPI's used 22 lb injectors vs. the 19 lb on 305's, but that was mostly for WOT margin. The '85 ECM isn't their best effort, but you can plug in an '86-'88 ECM and run the system slightly better. If it's an '87-'88 350 ECM, even better.

Weffy

http://cgi.ebay.com/ebaymotors/New-R...#ht_500wt_1125
Would this be considered a deal? I think that this is in my budget perfectly, and if I put my heads on the car, it would last a while.

I've been looking around all day for a 350 shortblock... no luck, nothing as cheap as that.

five7kid

iTrader: (14)

In spite of what the description says, it has dished pistons, which would make it a dog.

Try craigslist, racingjunk.com, etc.

{Edit: "This listing has ended"}

Weffy

Going to pick up a 350 now for $150... await the pictures.

Weffy

Crank is chewed up on the end where the balancer is. The guy gave me what looks like a piece of brass that he said to wedge in between the balancer and the crank and it'l be fine. The timing chain sprocket on the crank is also missing the teeth on half of it.

The heads and pistons look pretty good though. The block is .040 over already, and I got a nice set of roller rockers that came with it. Now all of the rocker arms/pushrods/lifters were mixed up, can I still use them? They also have dust and a little dirt on them can I just clean them real good?

Sorry that this thread has just evolved into the help-me-buld-a-350-a-thon

It is true though, everything is the exact same price for the 350 as the 305.

SeanW

Often the best way to buy a donor motor is too buy the whole vehicle. A guy will ask 500 for a pulled running 350 but as often as not you will find the same motor in a running beater for only a few hundred. Really what is a rotted out 1/2 ton worth in your area? My buddy just bought one for three hun, running needing only brakes and cab corners.

SeanW

Wow, this sounds scary. You really shouldnt reuse your pushrods but you can probably get away with it. Reusing mixed up lifters is a sure way to wipe a lobe. Just go buy 16 new ones.
Is this motor in pieces? Why? Why is the crank sprocket pooched? Why did you buy this???

five7kid

iTrader: (14)

You might be buying yourself a crank.

Jeremy Brown

ok hold on the difference between the 350 and 305 isn’t just the heads. Come on now. I’m a bigger fan of the 305 than the 350 and can rebuild both of them with my eyes closed

ShiftyCapone

iTrader: (7)

Are you the ghost of 305's of past? Bringing back from the dead old threads about 305's and how you think they are better? The 305 only existed to keep design and manufacturing costs down while meeting new emissions requirements. It is sub-optimal in all forms.

427seven

Originally Posted by Jeremy Brown View Post
ok hold on the difference between the 350 and 305 isn’t just the heads. Come on now. I’m a bigger fan of the 305 than the 350 and can rebuild both of them with my eyes closed

pretty much everyone on this forum knows that you need to keep yer eyes open when u rebuild an engine.....

Venom_1138

I can do plenty of things with my eyes closed... whether or not I do them depends on the degree of injury I'm willing to incur.