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iTrader: (5)

I just scored a Vortec 454 for my work truck. Just wondering what to expect when performing the conversion.

Truck: 1989 Chevrolet 1500 4X4, 5.7 TBI V8, TH350 (I think)

New Motor: 1998 Chevrolet 7.4 Vortec V8, 4L80-E (4X4 trans)

Also, anybody know the HP and TQ numbers on the TBI 350?

GOaT Cheese

I probably shouldn't reply 'cause I am not 100% on my info., but I think the '89 TBI 5.7L was rated at 210 h.p and 300 ft lbs tq.. As far as your conversion, it should be a cake walk. I think the two engines even used the same mounts. Are you going to put a TBI on the 7.4? If you use the Vortec intake, then it may get dicey with the PCM and wiring, but still shouldn't be that tough.

01WS6/tamu

iTrader: (37)

Change the cam. It makes it a ****** dog compared to what a big block should run like. I have the vortec 454 in my dd k3500. Before you say it's too heavy. I dropped it put 4:10's and factory 245's and the newer hd aluminum wheels w stock front and rear bumper. I've done every bolt on you can do and exhaust. Based off of the heads bottom end etc it ought to run like a raped ape. It is set up pretty much exactly like the 454 ho listed in the gm performance parts catalog only w a tiny cam tuned to meet emmissions. The only real difference is the cam which is much larger. I talked to a reputable performance shop we do a lot of business with and various customers of ours and everyone has bitched about the performance and pulling power. I am going to do a cam swap and have the pcm retuned for it pdq. We'll see then how it does.

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iTrader: (5)

I'm ditching the TBI and going with the new injection system, I think its MPFI... Yeah I am a little worried about the wiring but I'm sure I can figure it out.

Let me know the numbers with the new cam! I will be changing the cam and heads, I'll also put on a complete exhaust, from the heads all the way out the back. I plan on doing all this in May or June. For now all I want to do is put the new motor in, install a bigger radiator, electric fans and an electric water pump.

01WS6/tamu

iTrader: (37)

If you are using the vortec injection setup you cannot change the heads. They are not interchangeable between tbi and vortec etc. As far as the wiring harness and pcm goes you have a couple of options either modify your stocker which is not hard with some diagrams. If you need them I can send you all you need been through this on these engines. Or go ahead and get a standalone. THe heads on these engines flow very well from the factory is where they fuked us was the cam. A lot of these trucks got traded in on fords bc they would not pull and had lousy power. I have a book at the house that as all of the goodies on infor for these bigblocks. I'll look tonight and pm you the name. It has all of the good information to keep you out of trouble. Including how to get rid of the damm oil cooler "the bearing killer" later chris

01WS6/tamu

iTrader: (37)

You are also going to have to change / wait a minute if the truck you bought does not have the electric shift case you can use everything from the donor. But retrofitting the electronics is not hard at all if it does have the electric shift case.

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iTrader: (5)

I think I'm gonna modify the original harness. I'm hopeing it won't be very hard. Please send me those diagrams! That book sounds like a must have for big block owners, I'll be sure to pick up a copy when I get the name of it.

Electric shifting transmission or transfer case? I plan on using a manual shift transfer case.

01WS6/tamu

iTrader: (37)

I looked here last night couldn't find it. I think I have the book at home though I'll shoot it to you tomorrow night. It is specifically about gen 5 and 6 BBC's. Is the t-case out of the 98 a manual shift or electric thats what I meant sorry about that. The wiring is not hard. As far as going into your 89 just order everything for a 98 fullsize k3500 and it will bolt right in. This includes radiator, upper lower shroud, fuel lines from the block to frame, hydroboost for brakes, refrigeration lines, condensor everything. The only mods you will have to make will be to the core support but that is for airflow only. The BBC radiator and upper brackets will drop right in. But you will have to cut out about 4 inches to either side of the condensor in the coresupport. If I were you I would go ahead and pull the dash and swap in the 134 evaporator so it will have the right fittings and then use the condensor lines and everything so the cooling performance wil be factory and so you do not have to make any custom lines with adaptor fittings. The stock r012 condensor like your truck has sucks when you convert them over to 134 it's just not efficient enough. The motor mounts and motormount brackets from your 350 will nolt right to the big block and it does not have to move in the frame anywhere. I'd leave the stock exhaust manifolds and y pipe if you got it and build the exhaust from there. You can then use a fuel pump for a 96' chevy truck in the tank bc it is different it puts out more pressure but the sending unit is the same. If I think of anything else I'll let you know I'm still thinking about what you can do w your harness. Do you have a solid knowledge in vehicle electronics and engine management systems? That is the biggest deciding factor w the harness and integration into the existing

01WS6/tamu

iTrader: (37)

The book is rebuilding gen 5,6 Big block chevy engines. It's published by HP Books. Mike Mavrigian is the author.

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iTrader: (5)

The transfer case out of the 98 was an electric shift one. I couldn't get that though. I'd like to use a manual shift t-case in my conversion. Would it be possible to use a manual shift t-case that was with another 454/4L80-E combo?

I just have the stock manifolds, no cats or Y-pipe. I'd kinda like to use some smog legal long tube or mid length headers and just go from there.

I have a pretty firm grasp of vehicle electronics, if I have the diagrams I can figure it out. I also have a friend who is an automotive electronics wizard, I figure he can double check my work.

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iTrader: (5)

Oh ****! I almost forgot to thank you for the name of that book! I will definately pick this book up ASAP!

8a8mfh

iTrader: (3)

You can swap Gen 5 and 6 heads with Mark 4 heads. Victor makes a special gasket for doing this.

01WS6/tamu

iTrader: (37)

The transfer case that your truck has is the np241 it is the same regardless of bigblock or small block. There are only two things that you must have for it to work. One is the 4l80 adaptor that bolts to the back of the trans and front of the t case. Secondly you must change the input shaft of your t-case because the 4l80 uses a 32 spline output shaft. If you do not have one I may have a spare laying around somewhere. The other thing you need to get is the front driveshaft out of a truck w a 4l80 bc it is longer. I am assuming since it's a half ton your truck will have a one piece rear driveshaft so you can have it shortened. There is a second set of bolt holes on the frame for the trans crossmember to move back w the 4l80. 88-89 most have this set of holes if not just drill em no big deal though.

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iTrader: (5)

That's great that they are the same! I think I have that adaptor, I'll take a picture of it and post it tomorrow to see if thats it. I need an input shaft, if you have one I'll be more than happy to buy it. I'm gonna see if I can get a front driveline in Sacramento tomorrow.

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iTrader: (5)

I think this is that adaptor you were talking about. Do you have that input shaft, if not do you have a GM part number? I would really like to have one by November 17 if possible. I picked up that book, I haven't really got to look at it yet but I think it's gonna help me out a lot.

01WS6/tamu

iTrader: (37)

Thats the correct adaptor. I'll be dammed if I could find the input shaft for the t-case I found all of them but the one you need. I'll see if I can find a part number in the nex hour or so. Gotta call our parts guy

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iTrader: (5)

I think I found the part number but I could be wrong: 12386258. That right?

ws6on19s

iTrader: (4)

that motor rocks...i have a 97 gmc 3500 2wd 454 5 speed with a utility body
and have had it hang the front wheels and scrape the rear bumper...hooray bigblocks....my 03 f350 v10 is a turd compared to it

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iTrader: (5)

Hey, 01WS6/tamu, can I get those wiring diagrams? It's almost time for wiring!

Schurkey

There are TWO special gaskets, used when putting Mk IV heads onto Gen 5 blocks. P/N 4918 (right bank) and 4923 (left bank) The problem arises when using OLDER heads on the GEN 5 block. Since the Vortec engine is a Gen 6, you wouldn't need the special gaskets.

L-29 (and--probably--Gen 5) heads bolt right onto a Mk IV block, using whatever gaskets are correct for the block. I'm using Mr. Gasket steel shims on my Mk IV block/Gen 6 Vortec-head engine. Using the newer heads on the older block isn't a problem--at least the Gen 6 heads/Mk IV block works quite well.

Why can't you install the manifold/injection of your choice on the L-29 heads? My useage has an Edelbrock Performer RPM Q-jet manifold bolted to 'em. Same bolt pattern, same port location as any other Mk IV/Gen 5/6 engine.

The L-29 heads have a superb exhaust port, and a moderately crappy intake port. The intake is plugged up with a "ski jump" to induce turbulence into the mixture. The big advantage to the L-29/Vortec heads is the chamber and exhaust port, but the intake port needs real help.