How to ruin a near mint 85 gmc

[Rascal_one2001]

So I got a 1985 GMC short bed reg cab 305 th350 truck in a trade. Almost all original 30,000 mile local oldmans truck. Had old aluminium star wheels and dual exhaust so I had to get factory 8 inch ralley wheels and 235-75-15 Michelin Ltx m/s tires.

Put 5k miles on it and camshaft started loseing lobes. So I put in a built 700r4 a a TBI 350

Put about 5k miles on that and decided wasn't enough power. Now I have a truck with no engine in it and a built 454 on the stand that every time I walk past it I spend another $100.

[rusty76]

This ought to be fun

[Rascal_one2001]

Well finally dropped in the 454 and the built 700r4 and converted to hydro boost


Still waiting on another shipment of parts before I can bust some gas. Degreesed engine bay before installing engine and the firewall cleaned up nice enough I decided to only repaint the frame and cross members.

454: fully rebuilt 10:1 compression pistons
Block and heads decked
Comp cam
Heads reworked and valve job
Air gap dual plane intake
Fabricated valve covers

700r4:
Alto red racing clutches
Z pack 3-4 clutch pack
5 pinion planetarys
Beast sun shell
Corvette servo
Full custom shift kit
Heavy duty k case

[Rascal_one2001]

Finished up the hydro boost conversion and thanks to some helpful forum members I got the diagrams to do all my under hood wireing. Only waiting on my next parts shipment with my plug wires before I can. fire it up.
Bought a 12 bolt posi 3.73 on CL for $100 so at least I know my next project once I finish the engine.

[Rascal_one2001]

Got my truck running today runs good but its to loud with open headers to do any driving going to take it to the exhaust shop tomorrow. The truck has a good thump to it and a lot faster throttle response than I was expecting so I guess I am going to be putting a rev limitor box on it.

[MTCK]

Nice truck! I've always liked the red and black.

[ironroad9c1]

hope you put velcro on the bellhousing to the engine cause a built 700r4 can't handle even a moderate power small plock, much less a built big block.
clean truck though

[Rascal_one2001]

You are 100% correct about a factory stock 700 butI have my own trans shop I build 700s that have been put behind 700hp without problems. i build them everyday for 500hp cars and trucks as long as the cable is set and its built right (most everything upgraded) they are fine for 550-600hp. $1200 is our stage 3 build that will take 600hp

I decided to fab up a new cross member to make my exhaust install a little easier and cleaner. just built it out of some scrap 2x2 square tubing I had sitting behind the shop.



with the exhaust finished the truck is now driveable as far as noise but now I get to find out why my brakes don't want to bleed.

[Rascal_one2001]

Well I figured out that my master cylinder decided to crap out and start leaking out the back and my hydro boost either didn't like it or coincidentally crapped out so but in a new booster and master cylinder. The first master cylinder was set up backwards so my rear brakes locked as soon as I touched the pedal and the lines are different sizes so I couldn't just switch them so I order another new master cylinder it was a full metal and works correctly. Now my brakes function better than ever and I love the hydro boost pedal feel.

[jitteryguy]

very nice !

[jitteryguy]

Originally Posted by ironroad9c1

hope you put velcro on the bellhousing to the engine cause a built 700r4 can't handle even a moderate power small plock, much less a built big block.
clean truck though

you have been truly misled about 700R4's, I have run several of em in several different vehicle's include'n a daily driven V8 S10 with no trouble . there is a ton of misinformation about 700R4's out there.

[Greenlee]

Originally Posted by Rascal_one2001

You are 100% correct about a factory stock 700 butI have my own trans shop I build 700s that have been put behind 700hp without problems. i build them everyday for 500hp cars and trucks as long as the cable is set and its built right (most everything upgraded) they are fine for 550-600hp. $1200 is our stage 3 build that will take 600hp

I decided to fab up a new cross member to make my exhaust install a little easier and cleaner. just built it out of some scrap 2x2 square tubing I had sitting behind the shop.

Attachment 1167517

with the exhaust finished the truck is now driveable as far as noise but now I get to find out why my brakes don't want to bleed.

Nice looking truck! I like the cross member and exhaust.

I wish I had you or someone who knew what they were doing rebuild my 700r4. Mine only lasted about 1000 miles and I lost 3rd and 4th gear. After getting some really high quotes to have it rebuilt again, I got discouraged and swapped in a TH400.

[NASTY-LSX]

Originally Posted by ironroad9c1

hope you put velcro on the bellhousing to the engine cause a built 700r4 can't handle even a moderate power small plock, much less a built big block.
clean truck though

Ive had a few 454s with 700r4s and never once had a problem!, in my street cars

[Rascal_one2001]

well I ran my truck yesterday and put about 10 miles on it and its got enough power I feel bad for my right rear Michelin. It will break free when it kicks down to 3rd when cruising at 45. But after running it I pulled it in the shop to readjust the rockers and rocker tick won't adjust out so did some research and appears I have some of the stamped rockers that can't handle over .500 lift on a cam without clicking so I just made my order of a set of cromoly roller rockers $400.

[Rascal_one2001]

got my 1.8 roller rockers in today they look good and the clicking from the others maxing out is gone. best part is with the different ratio rockers my camshaft really came to life and my idle sounds much better.


best part of finishing my engine is I get to go cruising with my daughter who loves my truck. she said she wanted to stay in the truck instead of playing inside so we hung out in the truck till dark.

[Old School Low]

Hows the 700r4 doing? Is this basically a th350 w a 4th gear?

[Rascal_one2001]

I decided to lower my truck so I picked up some 3 inch bell tech drop spindles and a belltech axle flip kit with bolt in c notch. Since I was going to have the rear end out I swapped from 10 2.73 to 12 bolt 3.73.

12 bolt was a easy swap just had to get a special ujoint and all my 10 bolt brakes bolted straight on the 12 bolt

C notch was easy install just a lot of drilling
Drop spindles went in well just had to bend my brake lines a little

Front 5 inch drop 2inch springs 3 inch spindles
Rear axle flip gave me 6.25 inch drop


20 inch torque trust 2s
245-35-20 front tires
275-40-20 rear tires

[Rascal_one2001]

Originally Posted by Old School Low

Hows the 700r4 doing? Is this basically a th350 w a 4th gear?

Yes 700 kinda like a th350 with 4 gears. My 700 is doing great I drive the truck like I stole it every time I drive it.

[softballnrd27]

Any videos of it running? Way to ruin a perfectly good truck by putting a crappy big block in it and some ugly wheels!! LOL I like it

[Old School Low]

Good stuff Rascal This almost done 383 is going in 78 C-15. Will lower same as you did when piggy bank heals. [IMG][/IMG]

[Rascal_one2001]

Got some snow on it first night out of the shop.

[bnoon]

That's done up right as far as I'm concerned. Stock sucks except unmolested trucks are great to find so that you don't have to fix someone else's mistakes. Very nice.

[79azc10]

Nice truck. Love the stance and color

[Wrecked1982]

nice build! what year and model did your master cylinder and hydro boost came from? i want to put one with a plastic reservoir also on my 85.

[Low Elco]

Love the stance. Bet the 3.73's really woke it up!