Author Topic: 89-91 Frontend Conversion  (Read 20524 times)

Offline SUX2BU99

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89-91 Frontend Conversion
« on: March 08, 2010, 12:52:59 PM »
I've been trying to get this swap done for most of Feb. Getting there. Below are pics when I got the front end taken apart, and where it's at now. I relocated the B&M trans cooler to a better spot too. I kept getting weeping on the bottom hose. I hope I don't anymore and by having the hose connections at the top, I can take the hoses off and not get such a tranny fluid mess. Overall the swap is going well. Just have to do the wiring connections now to the old harness, get the bumper on and the new grille pieces in.

85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #1 on: March 08, 2010, 12:55:32 PM »
And here's a couple of pics of refurbing the park lamps. I am on the fence about buying new ones since I got the yellow tinge off the lenses. They are still a little cloudy though and beat up by road rash but at least they are way more clear now. I used a paste of baking powder and a Scotch-brite pad. About 5 min. of scrubbing the lense got the yellow off. Straight baking soda would have been more effective but baking powder has baking soda in it anyways. Cheap and effective!

85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #2 on: March 08, 2010, 04:34:17 PM »
Thanks. Yeah the 90 rad support that I bought had a trans cooler mounted to it the same way but on the driver side. It was the same size and type that my B&M is (stacked plate) but thinner and in not as nice shape. Borrowed the mounting idea and it worked out nice. Hopefully I won't have any more seepage from the hoses.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #3 on: March 12, 2010, 05:07:14 PM »
Thanks. Started on the wiring. Yeah that's going to be easy. The 90 headlights have two tan wires going to the low-beam plus the ground. I think the two might be because of the daytime-running lights that were mandated in Canada in 1990. That's good though because it provides a wire to hook up to each of the hot wires on my 85 low-beam harness. I figured out each of the hot wires on the 85 harness goes hot depending on whether I have the high beams on or not. But anyway, it's looking easier than it first looked.

The aftermarket lower valance panel went in pretty good. I had to tap it in actually because it was a snug fit but it went in fine. My core support fought me a little at some of the bolt holes but I got them all in without having to elongate anything. Had to use the impact gun on a few of the tight ones though  ;)

Hopefully I can get it all buttoned up this weekend.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline MarkS

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Re: 89-91 Frontend Conversion
« Reply #4 on: March 12, 2010, 07:34:02 PM »
So the front core support, fender, and subsequent grill trim alignment is working out good? I see from other posts you're like me and like things at least to look even :)

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #5 on: March 12, 2010, 11:38:58 PM »
Yes I'm picky when it comes to taking something apart and putting it back together. That's what takes me sooooooooooooo long. I clean everything up and try to make it like new again. Might as well right? I haven't got the trim pieces on yet. So I can't comment yet if everything has come together 100% yet  lol

Does it matter which way the headlight prongs go on? There's no real positive and negative, right? It seems like the high beam can go on either way. The low beam has it's posts offset so I think I got that right. It's wired up and ready to turn on but I don't want to blow some fusible link or something and spend tomorrow trying to track it down.

Thanks!
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #6 on: March 13, 2010, 11:18:05 PM »
Okay well I got it all wired up and tried it. Both high beams and one park light bulb came on.  ::)  Check bulbs and 3 of the 4 park bulbs are burnt out. Okay, easy enough. Both low beams aren't on though. Take off plugs and check power. Yep, power is all there. Plug back in and they flicker on. GM's style of connection wasn't exactly great, with just plugs sliding over prongs but I got those to turn on. Have to tweak them though so it's a reliable connection.

High beam foot switch though doesn't seem to be turning the high beams off so I have to try and figure that one out. I know that I got the right and left low beam pigtails mixed up so I end up having the extra wire on the passenger side one instead of the driver side. Not sure if that makes a difference though. I connected all non-black (ground) wires to positive power and all blacks to ground on the pigtails.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #7 on: March 16, 2010, 10:27:01 AM »
Got the wiring figured out. Here is some information that anybody doing this swap in the future might appreciate. I find it's little details like this which seem to be missing anytime there is a write-up about a swap to an 89-91 nose:

My 85 4-light system had 4 wires on the driver side low-beam pigtail and 3 wires on the passenger side low-beam pigtail. Drivers had two tan, one green and one black. Passenger side had one tan, one green and one black (well actually two black but one was to the firewall grounds and all blacks go to ground anyway so it's a minor point). High beams have only two wires: green and black

My 90 4-light system had 3 wires on the driver low-beam: two tan and one black. Passenger side low-beam had 2 wires: tan and black. High beams were the same as the 85: one green and one black on each high beam pigtail.

What I found was it does make a difference which side the 90 low-beam pigtails are on. 3-wire on driver, 2-wire on passenger. Here's the wiring tip: do NOT connect the extra green wire that the 85 harness had on the low beams to anything on the low-beam 90 pigtails. Connect both tans on the driver side to both tans on the 90 pigtail. On the passenger side, connect the one tan to the one tan and the black to the black. Do not connect the extra green wire on the passenger side either. High beams wire up without issue. Once I did this, my lights worked correctly.

I think this detail would help anybody doing this for the first time.

And some added tidbits that again, anybody doing this for the first time would appreciate especially if they don't have the donor truck right there and do not want or cannot make multiple trips back to where they got their 89-91 Sub/Jimmy/Blazer front end:

- get the lower valance panel, below the grille. It's 89-91 specific
- get the grille (of course) even if you plan to get a new one because you will need the little white snap-in screw anchors for your replacement grille, which doesn't come with them
- get the charcoal canister because your old one is riveted to the old core support and it's probably easier to just get the newer one, which mounts to the fender and not the core support
- take all the bolts and screws with you because you will probably need an extra here or there
- the 89-91 harness doesn't just plug into your older fuse box. Get the entire harness if you can anyways just because but all you really need is to cut the headlight and parking light pig tails off and splice them into your older harness as I described above. The side marker lights are exactly the same so no need to cut those off. Use your old ones.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline joesgarage71

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Re: 89-91 Frontend Conversion
« Reply #8 on: March 16, 2010, 10:03:26 PM »
 Those wires will come out of that firewall plug. I have gone as fas as taking the wires out of the plug removing the termails from the old wires, soldering new wires on the terminals for the headlights. I hate splices! Now that you got the headlights figured out, install a relay so all four lights come on when on High beam.
 The park light lenses can be sanded with (in steps) 320, 400, 600, 1000, and then use some alum. white paste polish. good as new. The same with gauge lens or your favorite sun glasses.

 Good Job! More PICS!!
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Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #9 on: March 17, 2010, 10:44:22 AM »
You have more time and effort to spend on that firewall plug than I do  LOL  That's the way to do it though! Sometime down the road (far, far down the road) I'd like to replace my old glass-fuse fusebox and update it. That's pretty far down the priority list though.

So success! Got the grille and headlights doors in. Pics are below. Had to redrill 3 holes. Bottom outside corners of each headlight door where the screw goes into the plastic anchor. Just had to redrill a hole in the anchor to line up the hole on the door. No big deal. And the screw at the bottom centre of the grille into the anchor behind. Minor. That's the only redrilling of holes I had to do on the entire swap.

My passenger side fender to hood gap is visible larger now than on the driver side. I'd like to shift the hood over but how can I do that when the hood bolts are horizontal to the hinge and not vertical?

Having purchased brand new aftermarket (offshore) replacement headlight doors and a grille, I can speak to the quality, fit and finish of them. I have no idea if one Chinese or Taiwanese company makes the reproduction parts that all of the online vendors, mail order houses, collision parts suppliers, etc. sell or if there are multiple and some are better quality than others. I bought the absolute cheapest, new parts I could buy. No I didn't buy them off Chris even though he sells them here but I went for the money savings and was able to find the grille AND doors for under $99, shipped. The odd thing was the grille from the vendor I bought from was significantly cheaper than any other vendor I found, perhaps for good reason. I almost think I bought a 'B' stock item even though the ad didn't say anything as such. Including shipping it was almost 50% less than other places I found. Doors were about 40% cheaper. 

Anyway, the parts weren't perfect. I expect new parts I buy to be perfect at least in finish. Fitment is another issue and has to do with how well the part is designed and made. The finish of my parts I normally wouldn't accept but I did considering their cost and because I didn't want to send them back and wait longer. The chrome has a couple of blemishes on it and there are some fine scratches here and there from poor handling. That's how they came out of the sealed bag. That is quality control I don't believe you would see from a North American-made product and hopefully wouldn't see buying the higher-priced parts. The scratches you wouldn't be able to see unless you got up really close and were trying to look for them. The blemishes would be difficult to notice if you weren't looking close. But what also bugs me is that they make these parts out of such thin material (thinner material means less cost and less shipping for the offshore manufacturer) that you can see some of the molding ridges on the smooth, chromed front side of the grille. I wouldn't expect this on an OEM part.

As for the fit, the grille fit pretty good actually. Very snug fit and everything but the bottom middle screw lined up fine. The doors fit decently well but it was more effort. For some reason they had these plastic tabs at 4 corners surrounding the parking light opening on the backside. These would hit the parking lamp housing. So I broke off the top 2 and they went in better. The bottom outside screw holes I couldn't get to line up with the anchor behind so I had to redrill holes in the anchor as mentioned above. And at the bottom they didn't meet up perfect with the grille but they did at the top and they hug against the fender nice and tight too.

Overall I'm pleased but if I have a reason to replace the grilles and doors in the future I'll pay a little more for hopefully a higher quality product. I have new park lamps on the way too so we'll see how those are.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline SUX2BU99

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Re: 89-91 Frontend Conversion
« Reply #10 on: March 19, 2010, 12:06:43 PM »
Got the bumper back on. I got it straighter too then how it was before. There used to be a very tight gap on the passenger side and a much more visible gap on the driver. I don't think the previous owner lined up the holes very well when he decided to put the 83-up bumper on the 80-down frame. Anyway, it's much better now. Pic shows how the headlight fits against the body and the grille. The bottom inside corner of the door sticks out some past the grille and I'm not sure how to fix it. I thought about heating the plastic and bending it but I don't want the chrome to possibly discolor. They fit nice and tight on the outside of the door though against the fender.

85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.