i was gonna put in a ls1 in my 99 xtreme just looking for some input. tell me about how your swaps went and any probs you had with them.

 

you will have to notch the cross member to fit the oil pan and if you already have the LS1 engine from a Camaro or Trams than The 5.3 Liter truck pan, oil pick try, tub, and indicator will have to be used. The corvette alternator bracket, power steering pump, pulley, power steering reservoir, hose, and balancer will have to be used in order to make clearness. It is also possible to shim out the alternator bracket ¾ inch to aline with the camaro, and trans am balancers, the stock F-body manifolds are the only ones that will work for s-10's. unless you buy some headers from JTR. if you want to have A\C you will have to cut more frame off the passanger side to make room for the compresser. you contat www.speartech.com tell them you want a wireing hanress for what ever year Ls1 you have, and want RPM,speedo, oil pressure, temp, vatts bypass, o2 simms, AT, or Manual trans, lets see what eles......yes you need engine mounts from JTR, and the (97) corvette fuel rail it has the regulator and return port on it and if your truck has a 4cly than you need to run bigger fuel line off a blazer or s-10 truck that had a 4.3L and a bigger fuel pump the 4.3L pumps will work you need 60-65 psi for the ls1 to run, and for the auto transmisson 4l60e you will have to drill another hold in the trans braket to mount it, and may have to cut your drive shaft back about 2-3 inches. you will need at least a 8.5 rearend off a 4x4 blazer. and 2 electric fans to cool your Radiator, and varies hoese. and about $3000-5000 if you do all the work.

 

Wow...That was alot, and hard to read. Next time, try breaking it up into paragraphs or sections or something.

Ok, lets try and straighten out some rearend myths here.
1.) There are 3 different rearend widths available for the S10. Narrowest is the 2wd, the std 4wd is 4" wider, and the ZR2 is 4" wider still (8" wider than 2wd). So, for the guy in question, unless he's currently using 2" thick spacers, he'll want a 2wd width rearend.

2.) Most Blazers and S10s have the 7.5 / 7.625" rear, relatively few have the 8.5" 10-bolt, so they're a bit more $$$.

3.) From what I understand, only 4.3 V6 5speed trucks got the 8.5" rear (starting in like '97 or '98), and it was available in all 3 widths (2wd, 4wd, ZR2). If you look hard enough, you can even find factory disk brake equipped 8.5" rears with posi / limited slip.

4.) Certain special models (like the Bravada) always have posi / limited slip.
For all other applications, posi / limited slip is an option and is dependent upon what the original purchaser / dealership ordered.

5.) (Warning - Opinion) The GM posi / limited slip that is installed in these rearends (both 7.5 / 7.625" and the 8.5" rears) is a complete POS. Its called an Eaton Gov-Loc, is weak, and has been known to grenade and wipe out otherwise good rearends. It is activated by a difference in axleshaft rpms (one has to be spinning faster than the other by about 100rpm), which means its more of a limited spin than a limited slip. And, once you're going faster than 25mph and let off the throttle, it disengages (so if you're cruising along at 30mph and nail the throttle (with enough hp), you get 1 wheel peel). Not the best situation, in my opinion.

6.) I think (but am not sure about) the Xtremes got the 8.5" rear axle. Would certainly be wise to identify it for certain.

There is at least 1 very informative post on BlazinLow.com that has information on how to differentiate between the 7.5 "/ 7.625" and 8.5" 10-bolts. You might check it out.

'JustDreamin'

 

fwiw i have a 98 2wd 4.3 5 speed but it came with the 7.5" rear.

 

jegs has a ford 9 inch bolt in housing with axle kit for s10's from currie for 964.99 a little spendy but easier than trying to find a 8.5 10 bolt pn 272-GMS8297X

 

I haven't seen any concrete info on the year the 8.5" was made available. May have even been staggered (4wd blazers starting in xx year, 2wd pickups starting in xx year, etc.)

But I do know they're available. Guy at my work has a '02 2wd pickup with 4.3 & 5 speed and the 8.5" rear. Checked it out and it has the correct casting features. But my '99 Bravada has a 7.625" rear (which is expected since its an auto, only trans available).

A little spendy? That's $1000 bucks for just the housing and axle kit. Then figure on at least another $1000 to $1300 for a centersection loaded with gears and a decent limited slip (like a Detroit True-Trac.) (Case is $350, gears are $200, install kit is $100, TrueTrac is $400). So, a complete rearend is only $2000 to $2300+.

And everybody thinks that 9" Fords are "bulletproof". Well, they're not. You can break them, just like you can break a Dana 60 or a Rockwell 2.5ton. And, unless you use all of the right pieces (big bearing pinion support, nodular case, 31 spline or higher axles, etc.) its not any stronger than the 8.5" 10-bolt that you're saying not to bother with. The real reason they're popular with roundy roundy racers is you can change gear ratios in a matter of 15 minutes or less. The GM 12-bolt is about the same strength as a fully built 9" Ford AND more efficient (makes less heat and puts more power to the ground). Figured you might want to know. I'll get off my soap box now.

'JustDreamin'

 

I never said not to bother with the 8.5, I just think they are harder to come by if I had access to one I would have one in my truck.But when I see them going for around 800$ on ebay plus you pay shipping for a stock 8.5 that gets spendy also.(Btw I checked the junkyards around here and no luck.)I plan on building mine right, to withstand a h&c ls1 6 speed with nitrous and slicks.Not saying the 8.5 couldn't take it but it's just easier to use a 9inch. Especially when all my friends are "roundy roundy racers"

 

I checked Car-Part.com....Found several pages each of listings for 8.5" rears in 2wd & 4wd. Almost all of them were under $800. Getting a good deal on ebay these days seems to be damn near impossible. And figure in the cost of shipping something that size, and you're right, its way too pricey. But if you can come up with a decent salvage yard piece for reasonable money, shipping it isn't so bad.

Anyway, if you've got buddies who are busy doing roundy roundy racing and can possibly get some cast off parts, then I'd say a 9" would be a good choice. But its not necessarily the best choice for everybody.

'JustDreamin'

 

Just curious, if your truck doesn't have the 8.5 rear could you use the smaller for awhile assuming regular street driving and no racing? I'm looking for an S-10 right now and would probably want to do the swap in stages....

And are the V6 chassis and 4-cyl chassis identical?

Sorry to highjack, thought the first question might be applicable...

Rob

 

My brothers truck is a 1995 Sonoma with the stock 7.5" 10 bolt, It has a Zexel Differential and a TA girdle and to date it has made 30 1/4 mile runs with 1.59 60ft times. It runs 12.01@111mph. The power output is 380-400HP at the tires. So for a while on the stock diff you should be fine but you might want to consider a girdle and a carrier upgrade.

 

woh guys not a noob to this. heres my whole swap plan. ls1 with trex, ungraded valvetrain, P&p heads, built 4l60e, ford 8.8 with 3.73 and a zexel, i was gonna get a custom built set of headers along with the exhaust, ls1 oil pan from JTR thats under production still, im not running a/c. its currently a 4.3 so i dont need to worry about fuel.the info on the corvette accessories was helpful. im planning on it being around 4.5k when its all said and done but ill save up another couple grand just incase, i dont wanna be one of those guys who stops because they run outta money. those 8.5 rears arent very good from what other s10 guys have said, they arent much better than the smaller one. i ahve an xtreme and it came with a 7.625 or 7.5. to my knowledge the only ones that came with 8.5 were the zr2 package s10 and 2wd or 4wd blazers. im hoping to get about 420 at the wheels and run like a 11.5 in the quarter with slicks of course. so do all of u guys have s10s or just a couple of u guys??

 

The truck in my sig is my toy, Currently working on my LS1 swap.

 

You never have done a swap have you? I can tell you this from experience on my S10 www.geocities.com/jays_s10/ls1swap.html take the amount of money that you think it is gonna take you to swap the motor over and double it particularly if this is your first time swapping said motor into said vehicle. You will run into things here or there that you didn't plan on. Anybody who has done a motor swap before can tell you that. Because you run into little unexpected things along the way. As for the 7 5/8 vs 8.5 debate, the 8.5 is the same rear that is run in the GNX's and turbo regals and you don't hear about them breaking a bunch running deep into the 10's alot of times. The 8.8 isn't a bad route and is probiably cheaper than finding an appropriate 8.5 but the 8.5 isn't a bad rearend at all. But like I said don't get caught with your pants down thinking it's gonna only cost 4.5k. Unless you already have the motor, tranny, heads, and wiring harness ready to go it's gonna cost a bit more than that. I have that just wrapped up in my motor and drivetrain. I'm gonna guess I have close to 6k wrapped up in mine if not more and it isn't done yet. Granted it's getting exhaust installed and tuned but it isn't done LOL.

 

Here's my take on the 7.5"/7.625" vs 8.5" rear end debate.

If you're running an auto and have a 7.5" in the truck currently, and its serving you well, leave it. If you break it, plan on upgrading, but it should last ok for a pretty good while. Pickups will be especially easy on them, since they have very little rear end weight and have a very difficult time getting traction. Its tough (but not impossible) to break a rear when the tires break loose first.

If you're running a manual trans, have the 7.5", and have done things to get the truck to hook up, start saving money for a heavier duty rear (like the 8.5"). I doubt you'll break the 7.5" in the first week (unless you're really trying) but with a manual trans and sticky tires / suspension setup, you're fairly likely to damage or break it. So, start setting aside some cash, and keep your eyes out for good deals.


And like Kossuth said, if you're doing an engine swap, plan on it costing more money and taking more time than you think. I'd say estimate it all out and then multiply by 2 (maybe 3 if the estimates are rough, 1.5 if you've got ALOT of detail in your estimate) to give yourself some cushion for the things that don't go right, or you overlooked. That goes for time as well as money. Many people don't consider the time it'll take (myself included).

'JustDreamin'

 

well im having ppl help me who have done engine swaps before so no worries. ive been researching the swap for about a year now so i know most of the ins and outs of the swap. im not gonna use the stock rear no matter what, im running over 400 whp, i know the rear cant take that. im planning on the swap taking me probly over a month to do but the big thing im doing is rebuilding the block, whichll start in the spring. tell me how ur swap goes black x.

 

I'm going the 8.5" route but it'd just be easier to get a rear out of a full size 1500 Silverado early '90s till the body style change it'll have larger bearings and 30 spline axles. Have it narrowed and build the rest of it to exactly what you need it'll prolly run about $1200-1400 and it'll hold the power no problem. Think about the 9" Ford it's big (space is at a premium on these little trucks) heavy (that allways sucks) and it needs alot of power to turn (read less power to the ground and that REALLY sucks) it is almost indestructable though. But you'll still be hanging some FORD **** under your truck I wouldn't do that for any reason, but then again I'm a bit F'd up when it comes to the whole Chevy vs. Ford routine.

 

im goin the 8.8 route, its teh same cost and its a little more efficient and most of em come with a 373 posi and disc brakes.

 

if i do the ls1 swap with my bravada can I keep awd?

 

The 4.3 4L60E and the LS motor 4L60E bellhousing bolt patterns are different. Might be able to use the LS tranny, just swap over the transfer case. Not sure you'll have to look into that somemore.

 

if your going to do that then why not go with a moser 12 bolt? 33 spline axels and a warranty. 12 bolt strength for $1375. i dont get it. everyone says what a good deal taking a junkyard rear is and dumping money into it to make it strong and its still not as strong as you can buy a brand new one for WITH A WARRANTY. the perfect rear for an s10 is the 12 bolt. because the 9 inch takes too much to turn and the 12 bolt is not going to break under a truck. the tires will break loose before the rear grenades.