Hello. New guy with my first 3rd gen, heck my first GM vehicle actually. I am swapping a 1984 corvette 350 into my 1984 trans am. My trans am has a locked up 305 h.o. Previous owner says a spun bearing, I have not had it apart to look, but the oil pan had more gasoline in it than oil. yikes. I'll mess with it later after my engine stand is free. Might rebuild it and drop in a truck.

I bought a complete 1984 corvette engine for $400 that I will be swapping in over the winter along with other work to the car. I have a Edelbrock 2701 intake for it and 1406 carb. I will get ceramic coated headers(shiny ones lol) a free flow exhaust and maybe some 1.6 rockers. Not trying to build a race car, just something fun to drive in the summer.

Anyway After I got the 305 out looking at the oil pans they are fairly different, which is not really unexpected. Any one know if the corvette one will clear the K member? I will find out when I go to drop the engine in, but that won't be for a couple months. Pretty sure I could use the 305 pan, but I'd rather use the corvette pan if I can. -Edit- I had searched before I posted but did some more after and found my answer. I'll need to use the 305 oil pan. I'll pick up a new oil pump and pickup and clean out the 305 pan.

 

Congrats on both the car and the engine. I installed '84 vette engine into my '82 about 30 years ago: in addition to using standard pan and pickup,had to make some minor modifications to the windage tray you will find on the 'vette engine.While the pan is off,check the little plastic collar on the oil pump shaft and also worthwhile to check the upper timing sprocket as GM was still using the nylon tooth sprocket in '84-( the nylon tooth ring shrinks with age and cracks off in sections) Also use 1 piece pan gasket going back together. One weakness of these "L83' engines is the #'624 heads: mid-1970s style 76cc chamber and prone to cracks-both between the valves and the EGR/heat riser "y" that is in the water jacket-cracks will allow oxygen into the cooling system and you will have rusty coolant in no time...I had the rust y coolant problem and replacing '624s with a set of Dart iron heads fixed that problem. TRW forged flattop pistons on the L83

 

Thank you very much for the info I did not know about the nylon parts at all. I will replace them with modern ones. Current plan is to buy a melling m55 oil pump, the drive shaft for it that eliminates the nylon bushing, the correct pickup for the original 305 oil pan, one piece felpro pan gasket and a melling double roller timing chain.

Hopefully the heads are alright for now. I could probably buy a set of reconditioned factory heads if needed after saving for a while, but aftermarket would be out of reach.

 

Or used Vortec heads and a "Vortec" style intake. Cheap and make a big power increase over the stock 'Vette heads.

 

What do you know and what do you not know about the Vette engine, I would be asking myself these questions if I were you.
Esp. if I did not see the engine running a.k.a..knowing the provenance of the engine...
If not best take the time to either go completely over the engine yourself or, if you need to involve a third party ?
A trusted mechanic or shop would probably save money time heartache yadda yadda. I know what I am talking about. Bought my
80s IROC with a blown engine. Engine removed in my backyard. Rebuilt by VOSS Racing Technologies. Engine reinstalled in my
backyard / transmission rebuilt + servos 1st and 2nd, in Jacksonville FL in all also in backyard. Therefore with confidence I can recommend you don't
want to have too many re-do's my brutha !

 

Story on engine is that it was a spare bought from a wrecked 84 c4 by a late husband for wife's 84 c4 with a 4+3. Bought from the widow for $400 along with the engine stand it was on. The guy hoarded parts and tools, the shop it was stored in was stuffed full. Engine turns over fully. Both throttle bodies are spotless, I have had the valve covers off. was clean, no sludge or corrosion. I will be pulling the pan within the next couple weeks(working on garage currently) so I will see what the bottom end looks like and get ready for new oil pump, pickup, driveshaft pan ect. But yeah basically as far as I really know its a paperweight. It's what I could afford.

I live on a very tight budget, otherwise I'd have bought a proper crate engine. It would take me a couple years to save 4 grand though.

Sadly before I knew about the possible cylinder head issues I had already bought a new intake maifold, hardware, gaskets ect for the pre vortec heads. crap.

I borrowed an engine stand from a friend for the old 305 so I can get the pan and engine mounts off it. and so i could move it when needed.

 

Sounds promising, so far. You can also put your 305's intake, carb and non-ECS distributor onto the 350, check the oil, then fire it up on the stand or floor just to hear it and see how it sounds before doing the labor of putting it in.

 

I have been thinking of building an engine test stand. hmm. I'll need a distributor though the original one to the car is controlled by the ecm, or at least appears to be a non standard HEI to me.

We are installing a natural gas furnace in the garage and working on getting more storage for parts/supplies setup. Once that is done I can get back to my car

Oh when I do the oil pump and pickup is one of those copper gaskets for the pump really as great some folks make it out to be?

 

You don't need a stand. You can set it on the ground w/a ~4"x4" block of cribbing (or two 2/4's) under the front part of the oil pan, and fire it up that way. I've done it w/the small block 400 I put in my Trans Am, decades ago. Blew one of my friends mind! "You can't do that!!"......vrooooOOOMMMMmmmm...la la la la la la la la la. The face was priceless.

OR you can put stand-off's and longer bolts on your engine stand, and put a flex plate on it and start it on the stand. I haven't done that, but would if the situation warranted.

 

My engine stand has built in stand offs that look like they may clear the flex plate. I did take the one off the 305 and it's in good shape. I'll see if it will fit when i get to it.

The 305 has what looks like a new starter and alternator. A retired mechanic I know works part time at auto zone so I'll go in on a day he is there and have him test em.

I did a tiny bit of work on it today, but man was it cold in the garage. I got the engine mounts off the old engine and removed the hvac fan. The previous owner hacked the a/c out and it's missing pretty much everything. Plan is to get one of the a/c delete panels not the complete block off so that I can retain heat in case i end up driving it in cold weather for whatever reason.

 

It'll fit; they're both neutral balanced, 2 pc seal engines.

 

Sweet, I was thinking it fit would but I was not 100% sure.

 

swapping engines in a thirdgen is so easy the car is the test stand When you install the 3 torque converter bolts,just snug them down,rotate engine through complete turn,the do final tighten.

 

What material distributor gear is the correct one for the 84 corvette engine? Looking at some distributors since i do not have a non computer controlled GM one.

 

Doesn't really answer the question but whether you have a flat tappet cam vs roller will dictate which distributor gear material you get.

 

Its hydraulic flat tappet. Pretty sure an iron gear should be ok but I just want to be sure.

 

this is the distributor I am thinking about orderings. https://www.speedwaymotors.com/Speed...ku=2896501-BLK

I have a new melling m55 oil pump, pick up, drive shaft, install tool, melling double roller timing chain and install tools, ceramic coated summit racing headers and a good bit of other stuff ordered. I was able to sell some stuff I had for sale for several months

Got the 305 oil pan off and mostly degreased. there was a broken off piece of aftermarket dip stick in it. some surface rust on the outside that will clean up well. I'll paint it after. Will probably stick with black.

 

I had to get rid of the windage tray entirely. The studs for it hit the trans am oil pan baffle. I used three of the mains bolts from the original 305 to replace the studs.

melling double roller timing chain fit without issue as did a melling m55 oil pump, heavy duty drive shaft and a melling oil pickup meant for the trans am. I set it to the same height as the original after driving it in half way then bottomed it out. it dose not move at all after driving it all the way in. Both me and my dad saw no need to have it welded. I used the $17 proform oil pickup driver. it worked great.

cleaned, rust converted and painted the k member and core support. waiting on a summit order with the rest of what I need to drop the engine in. We are currently swapping the rear end in my dads 96 trans am so will be a bit before I have room the drop the engine in.










Edit parts came in. Pretty much ready to drop it in other than installing the harmonic damper

 

engine is in.

 

Lookin' good!

It's hard to tell in the pic but have a look at that harmonic damper....it looks like it might be slipping rearward already.

 

Thank! Not sure what to look for on the damper. It is the one off the 84 corvette and is a bit different from the original one. I'll look into it.

 

Basically, the front face of the outer ring should be flush with the front face of the hub. The rubber insert that's between the hub and outer ring should protrude (or not) equally on the front and on the rear. You can't see the rear of the damper w/it installed but in that pic it looks like the outer ring has slipped and slid back some and the hub face appears to be "sticking out" further than the front of the outer ring. That will, at least, cause your timing marks to be off, making timing the engine more difficult than expected. At worst, the outer ring can slide back more and start slicing through your timing cover. When it slices all the way through, it'll leak a lot of oil.

 

It seems alright to me. When number one is at TDC the timing mark is right on. Spent a couple hours this afternoon cleaning up and painting the pulleys.

 

I have not given up, still working on it. Been going slow though. Partly due to hot weather, and we were getting my Dad's 96 trans am on the road.

Working on wiring and accessories before I can try and start it. figuring out the harness that the previous owner hacked up is not fun. And took a couple tries to get a throttle/TV cable bracket that fit. A jegs brand one worked out. Not a fan of the angle of the TV cable but it seems to move smoothly and adjust properly.

I picked up a OEM radio from a yard sale that supposedly is fully working for $5. Same as what my car has but a matte finish face plate instead of gloss. if anything I have a spare if I mess one up when repairing it. also got a hard cover chiltons shop manual for a couple bucks. that has been a nice help. Also got a non broken 84 front ground effect. Managed to find it on craigs list.

Tiny air cleaner is just there to keep things out of the carb when working on car.

 

Still picking away at it. I got a new throttle return spring bracket setup and working well, installed the radiator, but forgot to buy the hose clamps , got the starter wired the rest of the way up, new battery cables, Doug's stainless y pipe installed and misc odd n ends. Working on getting the rest of the old exhaust off, more wiring, and I need to get the blower fan mounted to the new heater box and get the heater core hooked up. It looks like it uses two different size hoses, and I only have one size.

since the air pump and cat were missing when I got the car I plan to run an aftermarket high flow cat. Yeah I could probably get away without one here, but I don't like the smell. And why give the anti gas engine folks any more ammo. Any way I gotta find the factory style flange because I do not want to cut up a $285 y pipe lol(it has the factory style flange/hanger) there is a guy fairly local that parts out 3rd gens, so maybe I can get the flange from him.

Also saving up for a decent mig welder and that has eaten up my spending cash. My trucks sheet metal needs a lot of patching up, and the trans am has a few spots to patch up too. plus some exhaust work on my truck. gotta love road salt

 

I would just get an OEM replacement cat (there is one available on RockAuto) and cap the AIR tube connection if you are not going to run an AIR pump. Not connecting the AIR system won't hurt the cat, but it just won't be quite as effective. It will still reduce the stink out of the tailpipe.

Trying to adapt a flange is going to be a pain since the pipe needs to be oval shaped, so using an OEM replacement is going to be your best bet if you are keeping the stock y-pipe.

The converters without AIR connections don't really work any better than the ones with AIR anyway, it's just that they use a different technology. They still need oxygen introduced into the exhaust air stream for the chemical reaction to occur, it's just that it is now done through programming of ECM to switch between lean and stoich during closed loop operation in order to intermittently introduce excess air into the combustion process. The new style converters then store those pulses of excess oxygen in reserve to be used up in the chemical reaction. If you run a new style converter that doesn't need an AIR tube connection on one of these old cars, since the ECM is not programmed to do the lean burn pulsing, the converter will be as effective (or ineffective) as a converter with an AIR tube that isn't connected.

 

None of the exhaust on this car was oval. Y pipe is aftermarket, but built to use oem convertor. No ECM left on this car. Has a edelbrock 600cfm carb and a standalone HEI. The electronic Qaudrajet carb was removed by the previous owner. The ecm, its HEI and what was left of the ecm harness is somewhere in a box of junk in the garage waiting to get scrapped.

I am using summit racing ceramic coated headers and this is y pipe the manual said to use. https://www.summitracing.com/parts/DOU-D901

this is a factory replacement convertor for this car https://www.summitracing.com/parts/m...s-am/year/1984

A lot cheaper to buy a $90 magnaflow or flow master universal high flow convertor and weld on a short section of pipe with the oem flare and flange cut off an oem convertor before it gets scraped.

I could cut the flare and flange off the y pipe and weld on an aftermarket convertor, but then I'd loose the exhaust hanger that bolts to the flange and I don't want to cut up the y pipe.

 

The OEM y-pipe on the '84-'85 305 HO was an oval pipe with a 4-bolt flange connection to the catalytic converter. That is what I thought you were referring to when you mentioned flange and factory replacement converter. This is the OEM replacement converter for an '84 305HO

https://www.rockauto.com/en/moreinfo...t=5808&jsn=930

I understand now what you are referring to with the flange. The Doug's y-pipe setup you have is for an '86-'89, which is a round pipe and the cat would have a slip fit in the front and the ball flange in the rear. The Doug's y-pipe looks to come with an extension pipe that has the ball flange and hanger bracket mount and eliminates the converter. You could cut out a section of that extension pipe and weld in a Magnaflow universal catalytic converter and keep the ball socket/bracket mount from the kit.

 

Just looked at the exhaust again. you are correct, the y pipe eliminates the convertor. When I get the rest of the exhaust parts and fit it together I'll cut a section out and install a convertor were it would have sat from the factory.

 

Looks like the y pipe is wrong. I could not get it to tighten down onto the gasket and did not want to force it so pulled it apart. y pipe looks like its for a different header flange. It is the y pipe the manual for my headers said to use. but I can't see how that would seal on a flat surface. Shown is the collector reducer that came with my headers and the y pipe.





edit: this is the contact it makes on the gasket. Maybe it is meant to seal like that? Any other header collector gaskets i have used made full contact all the way around

 

it runs! Got it started up Thursday. I still got plenty of work to do. Hope to have it on the road by summer. Body work other that dealing with the rust will have to wait. I want to drive it, and i hate body work lol

edit: whoops forgot to mention oil pressure is about 60 psi, and running voltage it at 13. temp gauge dose not work, I might have mixed up the fan switch and temp sender. Rest of gauges are working. The check engine light is very upset that the ecm is gone. I'll pull the bulb.

 

Finished the exhaust. The intermediate pipe was a pain. Used a walker 2.5" mandrel bent intermediate pipe, a AP exhaust excelerator chambered muffler and a single 2.5" tail pipe. And now that it is quieter I hear a noise that I need to trouble shoot. Hopefully just an exhaust leak.

 

Runs very smooth and sounds great!

 

Thanks! It starts very well too.

 

Yeah, sounds good. Maybe a loose-ish rocker or two?

 

Thanks. Yeah could be. I plan to take the valve covers off and check. Dealing with a cold at the moment so not much energy to work on it but will get it sorted out when I can.

 

The noise seems to be the passenger side header collector leaking. I bought some remflex gaskets to hopefully take care of it. I rebuild the power steering pump, cleaned the cooler, all new lines and a ICT billet bracket set for the power steering pump. Only took four trips to the auto parts store to get a belt that fit haha. ICT said 43", it ended up being 47".

Bought the brake hoses and hardlines. Cleaned up and rust reformed the core support. Rear axle will get the same treatment. Bought a BMR wonderbar. I've got a 84 front body kit piece that i need to paint to match the rest and got a air deflector on the way. Plan is to have it on the ground driving end of the month or early next month.

Oh yeah I Also switched to a 170 thermostat and a 185 on 175 off fan switch.

 

You've been busy! Thanks for the updates.

 

You've navigated a bunch of hurdles. Congrats!

Only thing I haven't seen addressed is the torque converter lockup. The TH700R-4 transmission has a clutch built into the torque converter that locks up under cruise conditions to improve fuel efficiency. The stock system used the ECM to send a signal to the TCC lockup solenoid, and you've eliminated the ECM (It used carb and distributor signals to determine when to do that, so even if the ECM was still there, it still wouldn't work). You can get a vacuum switch setup to perform that lockup function - or fab up a manual switch so you can do it yourself.

Oh, the TH700R-4 has a nasty habit of burning up if you don't have a TCC lockup switch.

 

I must have forgot to metion it. It is very important info for sure.

When I have confirmed the trans goes into all gears it will get a new filter, pan gasket, atf and a external lockup kit. I have confirmed it has the external port for it. So it will lock up in 4th automatically.

 

I'm not sure what "external port" you mean. The TCC lockup solenoid is in the pan. It is powered by a wire that goes to the external wiring connector. There is a 4th gear port on the transmission valve body that has a switch on it - tells the ECM the transmission is in 4th gear. That "port" can be used with a switch that locks up the TCC when in 4th. Is that what you mean?

 

This is the kit I am planning to use. https://www.summitracing.com/parts/aww-500412

It uses a pressure switch on the 4th gear pressure port near the shift solenoid to to trigger the lockup in 4th. Sorry I am not great at explaining things.

 

My '83 has a '84 700R-4 and no ECM.
I have an external lock-up kit from Monster. It is a pressure switch installed in the 4th gear pressure port. One side connects to the connector on the driver side, while the other side is powered by the brake light switch circuit (so it unlocks whenever the brake pedal is applied).
Make sure your lock-up solenoid is working before you put the new filter & pan gasket on, or you'll end up removing it all over again (ask me how I know!).

 

I'll look into how to test the lockup. Thanks for the tip.

I replaced the header collector gaskets. Passenger side was blown out pretty bad. Seems like there is still a leak in where the two parts of the y pipe connect under the oil pan. Dunno if that is the noise I am hearing or if it is vale train or worse? Kinda sounds like a diesel

Timing is set to 14 degrees before TDC with a timing light and it starts easy. So I don't think it's a ignition issue.


I found a set of four oem 15" trans am wheels for $125 that I am picking up Sunday.

Also bought one of the missing pieces of the air dam but looks like I am missing more parts.

 

We've been all over then engine with a stethoscope and things all sound normal. Going to pop the distributor cap and check if things are good. If that looks right valve covers will come off and we will go through the rockers.

We got the rear axle and suspension wire brushed and ready for rust reformer and paint.

Got my wheels, no curb rash but a little clear coat peeling. Very happy with em for $125. Plan is to get 215 65r15(stock for this car) mastercraft Avenger gt tires.

 

I'd pull the valve covers and check the rockers.

 

I will be, even to just be sure things are good for when I start driving it.

That said my Dad and I are pretty convinced the sound comes from the top center of engine near the firewall. I woke up feeling like crap today but did get he cap off the distributor. the advance mechanism has a ton of slop and everything rattles around alot. Cap and rotor feel like dollar store toy plastic. Seems like a good bit of slop in the shaft too. It's a cheap import hei from speedway.

Not saying I am for sure right, but it sure sounds like that is where the noise is

 

Pulled drivers side valve cover, one rocker a tad loose, one very loose. Passanger side is about to come off. Ill check things over and will go though and reset the lash.

Edit passenger side all seem fine.

Edit its the #3 exhaust and #5 intake rockers that are the trouble makers. Came in house to cool off. will get back out in a few.

Edit seems a little quieter with those two rockers addressed. Didn't have time to do them all but the rest seemed fine. probably will.
My dad is convinced it is the distributor. Me less so now. I do have used import HEI that a friend gave me a while ago. It seems a lot better built so I may swap them out.

We got the rear axle and suspension sealed up. wire brushed then rust reformer. Looks like there are a couple spots to touch up still. whoops

 

Make sure number 3 and number 5 are opening all the way....IOW, make sure a lobe or both aren't toast or getting toasted right now.

 

Probably going to run the engine for a short time with the driver valve cover off to make sure 3 and 5 are doing what they should be. It's been too dang hot and I gotta take a break. Going to be in the mid 90s today, already in the mid 80s.

Ok screw it ran it with the driver side rocker cover off.