Hey guys. So I started my engine swap. I yanked out the old antique boat anchor 305tbi and auto tranny and now I find myself scratching my head. I'm not overly knowledgeable on everything yet, this is my first engine swap. I know some guys may have the urge to type in "just do a search", but what's the point of this being a forum if I can't ask questions lol. Anyways, I'd like some opinions/advice on some things. Even if u just post a link on a swap guide or thread to help me out. I don't have much help with this either so I'm kinda on my own here. I'm going from my 305tbi auto to a 355 carb with a lt1 style t56.
First question is:
What do I do about my old wiring harness? Like I need some of it and I'm guessing I don't need some parts of it. As of right now I'm kinda on a budget, I just ordered a moser 12bolt rear with 3:90 gears, adjustable pan hard, adjustable lca, lca drop brackets, 3.5" aluminum driveshaft, Koni racing shocks/struts, spec stage 3 clutch with steel flywheel, hurst short throw shifter, subframe connectors and strut tower brace, air ride suspension, and a few more knick knacks. So I kinda want to just get this done cheaper and drive it!
Lol. What do you recommend I do to sort out my wiring? All I know is the 355 doesn't need half the wiring a tbi does. Will all of my gauges still be functional? Or should i make my own custom gauge cluster out of autometer gauges? Any help?

Next question is:
I'm planning on running a supercharger. My engine right now is running about 11:1 est compression with .100" flat tapper pistons (if that sounds right?) and a regular gm crank, new I believe. What do you recommmend I do to make my bottom end withstand the power addition of a blower? And what blower would you recommend? I'm running the ws6 style hood (which doesn't fit all that great :@) so I have a few more inches of hood clearance.

Last question!:
With that rear end, I want to run disc brakes, as I have drums on the rear now, and I want some good, drilled and slotted rotors but something that is easy to install, anyone have suggestions? Also upgrading the front brakes as well, anyone know of a good complete kit that works well with minimal effort to install?

If anyone is interested, I am selling the 305tbi and the 700r4, the stock rear end, which I guess has the 3:23 gears, it is posi, and a few more parts I don t need. Like I said earlier, I'm new to this, the only reason I.ve gotten this far is because of what I read on this site! So any help will be appreciated!

 

Do a

Sorry, couldn't resist!

The wiring...

Everything from the passenger side harness that comes out of fender at the heater box will go. BUT ... Leave it all there. It's a CYA thing. It all tucks away into the fender sight unseen - no need hacking it all out yet.

There are a few wires that run from that pass side harness, into the loom that runs behind engine, to the driver side. Things like fuel pump relay wires, fan relay wires, etc. Those, trace them down, cut them on the driver side, and tug them out through the loom, wrap with the others, and tuck away - that way you'll still have them JUST IN CASE.

In the end, 4 years later ... I still have my factory TBI wiring, still all tucked away. I use them sometimes - it's really nice to have a supply of cleanly installed wires that run from cabin (the ECM) to the outside of car. I've used for fog lights, manual fan on switches, exterior lighting, etc. Anytime I need a wire, I just dig one out, match it's colors to the inside half, and connect into it!

The rest I can't help with - I know nothing about the T-56 swap etc. Good Luck!

 

your compression is hella high you are gonna blow it on up re calc your design properly
aim at good compression for a turbo or supercharger is close to 9 or 8, 11 is insain.
make your own gauge cluster youll like it better in the long run...

 

have you already bought and paid for the rear end? If not, hold onto the cash.

What do you know about the bored 350? When was it rebuilt? What is inside it? How many hours has it run since it was rebuilt? You don't want to go through all the labor of replacing an engine when you don't know what you're getting.

You call the 305TBI a boat anchor but then want to sell it to someone else. Did it start and run for you every day? Are you confident that what sounds like a used engine that you bought will be as reliable. Young uns get all caught up on trying to make go-fast cars but I'll take one that starts and runs every day.

So, before you plow ahead, find out as many facts as you can about the engine that you bought.

 

Thanks camaronewbie, would you happen to have a picture of what yours looks like now? And what about the wires that run to the stock 700r4? Can they be re used in the t56? Is there any cutting and modifying the harness I have now to hook uP the 355?
And torque, my 305 started and ran every single day, not a hitch. Just not enough power. I called it a boat anchor as a joke, no disrespect meant by it.
The 355 is completely rebuilt, hasn't ran since it was just assembled a few months back. I didn't build it, bought it off a friend. The engine specs are :
1974 Chev 350 (.030" over)
Studded mains
Comp X-treme energy 296/302 split duration cam and Lifters (.530 lift)
Gear drive timing
Moroso push rods (with girdles)
Edelbrock fuel pump
Edelbrock Performer Rpm Air Gap intake
Demon 750 cfm Carbeurator
7000 RPM rated performance HEI
Tall Chevy Performance valve covers
14" x 4" (i think) K & N air cleaner
*1967 327 (double bump) GM heads
one piece 1.94" intake valves, 1.6" exhaust valves (Exhaust slightly O.S.)
1.4" double valve springs
1.5-1 ratio roller rockers
3" Mr. Gasket Headers
Aluminum pulleys
Chrome oil pan
Aprox. 11-1 compression ratio
Painted Dodge Daytona copper

It has a new gm crank, which I can't remember what it is specifically but I know its not one to handle a supercharger, also the pistons are new. I know 11:1 compression is way too much for a boost application, I'm just curious what you guys would recommend I do to alter it and make it handle the added power. Like which crank and which pistons and arp head studs and all that jazz, I'm not looking to build a race car, or something I'm going to pound the **** out of, I love my car too much and have way too much respect for it to do anything stupid, I'm going for more of a look and show car while having the added power in case I take it to the track or something. Like I said, I'm new to this and I'm trying to learn as I go. I'd appreciate any help!
Yes I already paid and bought the rear end, I know this engine is every bit of what I think it is. Only thing I don't know is the exact hp of it. It was estimated to be around 400 give or take so I won't know till it hits the dyno. Ive been meaning to post pics but I can't do it on my iPhone. If anyone wants to see the car/engine and if u have facebook, add me, Kyle holloway, and you will see it.

 

Right, hold onto the cash so you have it for the tow back home when you grenade the stock rear end, leaving you on the side of the road.

I applaud you for spending the money to handle the power you plan on making. A very rare trait around here. Manual trannies are very hard on rear ends, even on the street, so upgrade it before you have the power and manual tranny installed.

 

The 700R4 wires won't be needed - well, not some anyway. The 4 prong wire conector only controls the TC lockup - since you won't have a TC (manual tranny swap), no need to lock it up.

Speedo cables/wires are a different story - but I know nothing about swapping to T56, so I'd try looking in the tranny section for help/answers on speedo connections.

Not the best pic, but here's my bay now - post 10 in this thread: https://www.thirdgen.org/forums/body...clearance.html

 

Thanks. I still don't get my you guys are telling me to hold off on my rear end? I'm not using the car until it's all built to handle the power I'm going to be running. The manual I bought is in very good shape. Shifts smooth, I was just going to order a spec stage 3 clutch and a centerforce flywheel to mate it to the engine. And instead of leaving my stock rear end in only for it to grenade first time I dump the clutch, doesn't really make sense to me. I'm willing to spend whatever it takes to make the car reliable and run smooth. It's my passion. And to think... I was going to sell it... Hahah!

 

Thanks for the pic camaronewbie, hopefully it helps out. I think I understand how to make the t56 function now, its just which wires to run where on the engine is where I'm not fully sure about.

 

ummm

perhaps you misunderstood?????

My point was to find out about the engine and use the money to repair if needed. He since posted that it's documented as to what was done, thus, my concern was unfounded.

 

nobody has

I can only reply about my post where I asked for you to verify the engine before dropping cash elsewhere. Why buy a rear end if you bought a junk engine ?

 

If you're getting a T56, then the stronger rear is warranted, even if you keep the 305. Between a T5 and a 10-bolt, the T5 is the weaker sister. But, a T56 changes all that.

Whether the 350 is junk or not is a completely separate issue.

 

The 355 is definitely not junk lol. It was professionally built and assembled by a guy I know who's been building engines his whole life. The t56 came out of a 93-97 ta with lower miles, I'm not reusing my 305, I'm dropping the 355 in. It's a show quality engine, estimated to be around 400hp. I bought the eng and then decided I want to run a blower. All the engine will need is a stronger bottom end (pistons, crank, etc.) money isn't an issue, the rear end is already bought, and the t56 is already bought, the 355 is torn down to the block, and I'm contemplating on replacing the internals to run a blower. That way, it's all done when Im ready to drop it in. I'm just wondering, as I asked before, what do u guys recommend for crank/pistons/etc? I'm not on any budget, pretty much all the money I'm making is going into the car until the day comes to fire it over. Also, if anyone knows where to get some slp 1 3/4 headers, let me know!! Thanks!

 

ok guys i finally got a chance to upload pics of the engine and car and stuff. heres a few pics of the engine and the tranny i bought to go in. now does everyone see what im talking about? aha

 

well as far as the wires go, i cant help. that stuff confuses the deuce outta me!

i wouldnt supercharge it. your compression is too high and the only way of bringing that down is to get different heads. plus you would more than likely need forged pistons, rods and a crank which it doesnt sound like you have. thats just more money.

and brakes? i would keep the rear as drum so you can power brake! yay! in the front i would go check out summitracing.com they have a baer slotted disc brake system for third gens that can shed up to 35 lbs off the front end!

hope this helped!

 

Ive decided not to supercharge it this year. Unless I win the lottery. Lol. I'm definetly going to check that program out for sure! Hopefully it doesn't let me down! Aha. I know my compression is too high. It's the way I bought the engine tho. I still want to convert it to 4 wheel disc tho cuz I think I'm going to enter an event called targa Newfoundland. It's time attack races back in my home province, that they close streets down and you race thru your neighborhoods and stuff. Check out the website if u want to know more about it. Ppl from all over north America can enter the race. It's really cool. I just want to have a good handling when it comes to that. Only downside to the event is all vehicles must had a roll cage, in the wide open mod class, which is the only class my car would be able to enter. There's a couple third gens that race in the event now and actually do very well.

But not to get side tracked...
What have you done to your 85 so far?

 

Well 11:1 isnt too high if you are going to keep it N/A. Thats what mine will be (in about 6 years when Im finally done building it!) Haha! And ya, 4 wheel disc is better if thats what you are going to do. Just dont neglect the suspension! Get a strut tower bar, weld on sub frame connectors, better shocks and struts etc.

As for my car, I too have very little time to do anything to it, and even less money! But heres what I have done....

Small tube headers
True dual 2 1/2" exhaust without the cat
Ported plenum
Performance plugs and wires
Throttle body bypass
A/C deleted
Smog pump deleted
Heater blower and core deleted
Cruise control deleted
Washer fluid reservoir deleted
Wipers and motor deleted
Homemade cold air/ram air intake
K&N air filters
Rattlecan paint job
IROC spoiler added
Duraflex ss hood added

I think thats it or maybe thats all I can remember but I got big plans!

388 c.i.d. TPI motor est 430HP (bout $5k to build)
Moser 3.73 posi rear diff ($3k)
High performance 700R4 ($2200.00)
Edelbrock performance suspension package ($1k)
Baer front disc brake system ($900.00)
Gloss paint job with racing stripes ($250.00 done soon by me)
Re tint windows ($180.00)
LED taillights ($400.00)
IROC 18" replica wheels ($800.00)
New front tires and 2 street slicks for the rear ($1k)
Lightweight racing seats ($250.00)

And the satisfaction I get from doing it with my own hands and having the car Ive always dreamed of??? PRICELESS!!!!!!!!!!!

There might be some other misc. stuff I forgot to list but you get where Im going. Ive also shed about 200 lbs off my car with all the crap I did! My goal is to get it to weigh 2900 lbs or less with me and a full tank of gas!

So what do you think?

 

I think if u could get the car down to 2900 lbs it would be sick! What kind of headers did u go with? I also have a true dual exhaust and I love it! I can't wait to hear it with the 355! Do you have the engine you're building the 388 out of? If I were to pick an engine and build it myself I think I'd go the same rout and build a stroker.

I'm currently working on my suspension now while I'm waiting for the clutch and flywheel to arrive. I bought a 12 bolt moser rear end, 3:90 gears, umi torque arm and LCA's, subframe connectors, I bought Koni racing shocks/struts and now all I have to do is break down and buy all new disc brakes. I'm hoping it's all going to be worth it. Spending enough money in it that I could buy a new car lol. I'm currently in the process of removing the old rear end now.

Did you ever think about going to a manual tranny instead of the 700r4?

 

The only wires you will need to get that motor running and gauges functioning are for the starter, alternator, distributor, coolant temp gauge sender, and oil pressure sending unit. label these wires if you have not already done so. You will also need to run a ground strap from the rear passenger head to the factory location at the firewall.

This is of course assuming you are running a non computer controlled distributor and carb.

Are you running an electric fan? If so you'll need to hook up its relay as well. Sorry can't help you there...

If you want your heater blower motor to work there is also a ground on the HVAC wiring harness that you will want to make sure is still hooked up.

Let me know what coolant temp sender you decide to use and where you end up installing it. The stock 305 coolant temp sensor is too small to screw into the driver side head location on your 350 block. I had trouble with this on my 350 swap.

 

Just realized you'll be running an engine driven fan so no electric fan wires and relays to worry about.

Do yourself a favor and pick up a new fan clutch and make sure the lower air dam is still intact or your nice shiny new motor will heat up real fast. Don't ask me how I know!

 

Not too sure what headers I have. Just went with what the guy who put em on reccommended. Flotech smalltube I think.

I didnt want to go with a 5speed tho. It is lots of fun to drive a 5speed but it gets old when you do alot of driving. Plus, on the 1/4 mile, you lose speed on the shift with a 5speed vs an automatic.

And I do have my engine block. Nothing else yet... Haha! Heres what I have and whats been done to it...

350 4 bolt main
2 piece rear main seal
Gen 1 small block
Bored .060" over
Aligned honed
Decked to 9.005"
Grinded the lifter valley return holes
Painted/sealed lifter valley (500 degree engine primer and enamel)
Painted block black (500 degree engine primer and enamel)
New freeze plugs

Heres the pic...