How to swap a big-block into an awd Astro/Safari...

[peter]

.....without that many pains. Only prerequisite is that you want a lifted truck. This swap was relatively easy, but my "expendable cash" made it easier for me. It'll make it easier for any of you wanting to do the same swap...

EDIT: I'll be going back and adding/correcting info once in awhile as I see where relatively important info is missing/erroneous. All info added later will be in a blue font. If anyone thinks this isn't a good idea, lemme know and I'll remove the coloured font.
First thing I did was to go out'n buy another Astro/Safari. My gf needed a vehicle to get to work, and we live out in the boonies. So the plan was to purchase another truck of the same year, pull the front sub-frame from it and use that subframe only for designing the motor/tranny mounts etc. In the end though, I decided to simply refurb the donor frame and install it in my truck when ready.


First thing we did is to cut out the cab section of the donor truck so as to be able to gauge what clearance issues we'd have. I was really nervous about whether or not the doghouse would gimme enuf clearance for the big block. The luxury of having a cab to use for clearancing was immeasurable...




Fitting the engine/tranny/t-case was a one day affair. By that, I mean that it took us a whole day just to set up the combo just where I wanted it AND make sure that it was sitting perfectly straight in the frame. I was deathly afraid of mounting the engine cockeyed which might cause vibration issues or god knows what else. Keep in mind that this was the 1st swap I'd ever attempted, and I sure picked a challenging motor to swap in...
To make it simple(r) for anyone contemplating the swap, I ended up using the stock tranny bellhousing location as a reference point. In other words, the 4L80 bellhousing mounting flange is exactly in the same place as the OEM 4L60. By doing this, I was sure to not run into clearance issues between th rear of the block and the dog cover opening.





Modded transmission mounting perch. Yeah, mebbe over-engineered. But at least it won't break off LOLOL







Engine mounts. Used the OEM mounts from the 4.3 (but brand new) and built adapter plates for 'em








Here's where the cab was invaluable for fitment testing. Remember, the green cab is the donor cab.

[peter]

One major pain in the butt was the accessory drive bracketry. I had initially purchased a kit thru Ebay which supposedly adapted my 4.3 bracketry to a big block, but it didn't fit. I broke down and purchased a complete accessory drive kit including the drives AND the bracketry. Cost me about $1,100, but in reality, that wasn't expensive. Remember now, for $1,100 I got a brand new GM power steering pump, alternator, A/C compressor, reverse-rotation water pump, idler pulley & brackets. Since I was gunning for dependability, replacing all these parts separately (and prolly using jobber parts) would cost me as much as the complete OEM kit. As well, the time I saved NOT having to screw around with bracket mods was invaluable.



One of the smaller issues was with the placement of the HydroBoost. While it didn't actually touch the engine or related bracketry/accessories, I was worried that there would be interference when the engine torqued over in reverse.





So I modded the bracket which holds the master cylinder so as to shift the whole assembly over to the driver's side but about an inch. I removed the 4 bolts which hold it to the firewall & filled in the remaining holes. I then drilled 4 new holes to accomodate the same bolts, all the while shifting the whole bracket over by an inch. Again, this is all stuff which woulda made the actual swap drag on longer and longer (meaning more down time of my truck) if I hadn't had the luxury of using a dummy cab for fitment.

OEM master cyl. bracket with the holes filled in;





Here my completed subframe, complete with brand-spanking new big block 502 horseys, waits patiently for a transplant into a worthy recipient




Here the "donee" waits for the "donor", though not as patiently





While in the garage with it's insides hanging out for all to see, I started installing the 2-speed part-time t-case shifter. Again,the placement of the shifter and basic bracketry design was already made/clearanced using the donor cab











Wiring was an issue for me. I'm used to doing electrical/wiring work, but I wanted to retain my air bags/ABS/cruise control/speedo etc. That meant deciding which wires weren't needed anymore, which were which and how the heck to figure out which was which. I have to admit the task seemed intimidating at first. Incredibly though, I managed to NOT screw up anything the first time around...










Looks so easy, don't it. Fact is, it was

[peter]

And slowly, the swap began to come to a close. You can see the increased clearnace between the master cylinder and alternator in this pic




Baby's finally home....




Spark plug replacement on this truck (due largely to the 5" body lift) is embarrassingly easy





Mounting of the CompuShift transmission controller which controls (duhhhh) the 4L80E tranny I had built/shipped from PATC tTransmissions in Louisianna. This thing is freakin' incredible, and customer suupport is incredible. The controller smoked to death on initial powering up. I was sure I'd screwed up with the wiring but it turned out to be a defective capacitor in the controller. Compushift asked me to send my controller UPS Red-Label, had it fixed and shipped back Red Label within 3 days. Freakin' incredible service!!!





The controller was finally mounted above the carpet, this was for fitment purposes only




The optional display. This thing blows my mind. I thought I'd ordered the controller without the display head, thinking it was bling-bling I didn't need. I was surprised to see it shipped with my initial order and realized what a mistake it woulda been not to have this. It allows you to custom tune sooooo many different parameters, it's sick.

[peter]

Believe it or not, rad hose routing was one of the more time-consuming things I had to do. I ended up loading half my local auto-supply store's hose inventory and mixing/matching/cutting/modding two of 'em to fit. The lower rad hose went well, I used the original 4.3 hose. The time-sucking task was identifying each hose being returned and hanging it back up on my auto-supply store's wall




Mounting of the IAT (air-inlet temperature) sensor in the filter. GM loves to contradict themselves. They mounted the IAT in the upper intake manifold, then stipulate that the sensor should never be mounted to a warm part of the engine due to possible false readings. Idiots....



Engine compartment's starting to look cleaner'n cleaner, thanks in part to a custom bent piece of stainless fabbed up by a buddy of mine which acts as a rad cover




I originally mounted the Flex-A-Lite temperature probe in the rad as specified by Flex-A-Lite. I didn't like the variations in fan-cycling temps (I know, I'm anal LOLOL) so I mounted the probe in the top rad hose where the hose adapts to the smaller rad hose. The temps were much more acurately held due to this relocation. Later however, I reloaceted this probe directly to the passenger-side head, which resulted in a cleaner look and even more accurate temp control.




I wanted to be able to have a visual indication that the truck was in 4wd, so imagine my surprise when I mistakenly found out that my pre electronically-controlled awd system had an "awd service" indicator lamp in the dash just the same. I isolated the lamp from the rest of the printed-circuit board, used the bulb/holder from the SES location and Bob's your uncle. It's perfect, except that it says "AWD" instead of 4WD. We were gonna black out the little leg on the letter "A" so as to spell "4", but it looked crooked so we didn't. We did black out the "service" part, though.

[peter]

These are the manifolds I decided to install on ZZ. I've personally had headers on at least 4 vehicles I owned in the past, and will never do so again. Between the bolts loosening, the flanges leaking and the premature rusting, headers do little to beckon me anymore. As well, the header tubes seem to cause higher temps to surrounding wiring/hoses etc, simply because they take up more space. I wanted to have relative peace of mind for exhaust leaks, so I went with these stainless steel OEM manifolds which I purchased used thru E-Bay. Cost me a small fortune to mod them, but I'm happy with the relative dependabilty. Prolly also cost me around 25-50 horses, but it's a trade-off I'm more than happy to make. Especially for a daily driver


Before mods




Some of the clearance issues I had before the mods






I had to remove the flanges so as to re-orient the manifolds to clear the subframe on the passenger side, and the t-case front driveshaft on the driver's side. By "removing", I mean grinding out the OEM welds between the manifold flanges and the headpipes and separating them, as well as removing the restrictive A.I.R injector bungs. Removing the OEM welds so as to spearate the flanges was a long and tedious job...




We re-welded the manifold flanges after tacking them in place when they were in the position I wanted, and covered up the injector bungs. I also had the outlet extended on the passenger side so as to eliminate the exhaust/frame clearance issue. I got reamed by a "good friend" of my brother's who owns a machine shop. I had the welded-up manifold flanges surface-ground and also had custom stainless flanges fabbed to hook up to the exhaust pipes. No, they may not be pretty but they don't leak, weigh nothing, are more efficient than cast iron manifolds, especially with the restrictive AIR injector bungs removed (though admittedly not by much) and no exhaust leaks.




I used the throttle cable actuating cam thingamajiggy from the 4.3 on the big block. I didn't wanna have cable length issues and wanted to be able to use OEM stuff as much as possible. I was also adamant about using all the accessories including the cruise control. A bit of welding here and extending there and it all worked out







The only slight drawback with my cruise control is that the OEM computer and/or cruise control module still thinks there's a 4.3 under the hood. So when driving down the highway at 50-65 mph, the cruise control tends to overaccelerate slightly while maintaining the proper speed setting. What would normally take 25-30% throttle to maintain 60 mph takes only 13-17% with the big block. The cruise control module simply overcompensates rather than take baby-steps LOLOL. On the other hand, the only time I ever go anywhere on a long highway trip is when I'm towing the Tramper. When towing her, I need around 20% throttle to maintain 60-65 mph and the engine & ground speeds are then rock steady.

[peter]

It's not "quite" as simple as the pics may seem to indicate. But honestly, the swap went better than I coulda imagined. After a coupla months of working out little insignificant bugs, and due to the incessant teasing by my employees who all clamied I'd be stuck on the side of the road all the time, I decided to go on a "Smurfster Tour". Drove thru NY, PA, OH, KY & GA before arriving at my final destination at my friend Midgets place in Cape Coral Florida. I had one non-swap related breakdown in OH which turned out to be a blessing in disguise. I had the truck towed to a local tranny shop the next morning where they removed the passenger side shaft and I was on my way again. BONUS!!!, The truck was running smooth as glass now. Highway driving exhibited absolutely no vibes whatsoever. Although I had promised myself to keep speeds to 65 mph and lower (partially due to the unnerving vibrations), I now found myself running at speeds as high as 85-90. Felt like I was floating on a cloud...

I had had this annoying vibe at 70- mph & higher which I assumed was because my driveline angles were possibly off. Turned out to be because of an S-10 passenger-side front diff bracket being used with the S-10 axle-disconnect diffy which I had pulled off the donor truck. The difference between the two brackets is practically nil, but it was enuf to cause my front diff to be cocked lower on the passenger side & higher on the drivers side. This in addition to the steering stops on the front of the lower A-arms having been ground down by some idiot (remember, this subframe came off the donor as well) caused front cv angles to be pushed beyond design parameters. So anytime I'd be in 4wd (as was the case the night I blew apart the cv joint in Ohio while visiting Logan & Mandi) and would turn the steeri ng wheel full-lock left, the passenger-side cv joint would blow apart.


Long story short (yeah, right LOLOL), the truck starts & runs great and is actually my winter driver as well as Mustang Stomper. 1/4 mile times aren't as low as I'd like 'em to be, but running fat 31" AT tires on heavy 10" wide custom steel rims don't help. At least I got into the 13's. I intend to run her this summer with 27-28" street tires and hope to come back with timeslips in the low to mid 13's.
Git 'er dun!!!!!!!!!!!!!!!

[SafariRob]

It was good seeing this post again, especially since I finally got to see the brute Safari in the metal last summer at NECO 07. Hey, I even got to ride shotgun in it when Lockdoc noticed that Peter had forgotten to remove the keys from the ignition switch.
Here's how it went:
Lockdoc-- "Shoot dang, Rob, Petey done fergot to yank the keys! You thinkin' what I'm thinkin'?"
Me--"Wooo-hoo! Let us climb in and fire this here puppy up for to create vehicular mayhem while cruisin' for wimmins!"

Which we did. Well, except for the wimmins part.

Holy guacamole, is it ever impressive--all kidding aside. It has to be the first vehicle I've been in that, while climbing a grade, up shifted when Bill gave it more throttle; all my instincts told me that the van should have down shifted, so it was a very noticeable event. It was as though the 502 didn't have a load on it at all or that the road was level, and believe me, in that part of Pennsylvania nothing is level.

As the photos show, Peter has done a very professional job of dropping in the 502. I climbed all over and under the van while at NECO and nowhere did I see anything done in a hasty manner.
Nice work, Peter.

[peter]

Thanks for the compliments, guys. The honest truth, there ain't much I'd have done differently. Assuming, of course, that I was still hell-bent on blowing $30k+ on a 1997 mini-van

[91AWDAstro]

What strip is that at?

[peter]

That was at Napierville Speedway here in Quebec.

This thread contains only 10-15% of all the pics and details that went into installing this engine. And still, I consider it to have been an amazingly easy swap, all things considered. To be clear though (and I've mentioned this before), the 5" body lift as well as the donor truck cub made this swap a relative breeze and made me look adept..

Now it's time for someone to pull off a diesel swap

[1996astro]

Peter,

What did you do to make those sub-frame mounts? That looks much stronger than using blocks. Also how did you get the bumper to line up? 502 in an SAFARI who would have thought...

Thanks

[peter]

Peter,

What did you do to make those sub-frame mounts? That looks much stronger than using blocks. Also how did you get the bumper to line up? 502 in an SAFARI who would have thought...

Thanks

Schedule 40 5" (I think) piping, cut'n capped to 5" height. Welded to the subframe. The truck handles better now than it did with the 3" plastic body spacers I had there before.

PS: You ever call my Safari an Astro again, I'll track you down and mount you in front of your pet dog!

[1996astro]

Awesome Peter thanks for the info on the lift. But how did you make the bumper line up?

As far as the Astro comment I am truly sorry. According to your write up the sub frame is from an Astro since made into the tramper. Which lost its front end for mock up of the project resulting in your 502 Safari. So your Safari has some Astro connection...

I do like the Safari front end better than the Astro, but I seem to keep ending up with an Astro.

Your threat of the mounting makes me want to move south further away from Canada (I have seen pictures).

[peter]

Crap, you gotta point. There is Astro blood in my Safari. How could I have ever forgotten that...?

Raisng the bumper is simple enuf. You simply cut the mounting flange off've the braket and raise it using angle iron or plate steel. Really not complicated at all. I'll see if I can dig up a pic.

[peter]

She left for a week and is Florida, still not enuf time to build anything...

I did build the Tramper after that, used the carcass from the donour truck. I suppose I should do a write-up on her as well, huh?



PS: Gawd, I'm such a show-off....