IRS Rearend

[82mystery]

Irs Rearend

i am thinking about putting a 550hp and about the same with torque small blk in my 82. i was going to beef up the rearend with solid u-joints and hd half shafts along with new gears in the case. should i just forget the irs and go with a dana 60 or ford 9 inch? any one ever done this? thanks larry

 

[AKRAY4PLAY]

i am running 606hp and 588ft/lbs in my small block. i also have done nothing to the rearend except install the VetteBrakes dual mount fiber spring and cam rod kit, a must for any performance Vette. i am running 255/60/15 BFG radials and a 3.7 rear gear. no problems for the last year and a half. i would run greasable u-joints instead of solid. DanaSpicer heavy duty joints are as strong or stronger than solids. i have researched many u-joint tests and they all said the same thing, run greasables. greasables break in the body and solids tend to break the pins off. it all boils down to alloy strength, not zerk fittings. most 4x4 mags will have articles about u-joints. street tires in the stock size range will allow some spin and lessen the load applied. if you are going racing with slicks, look toward the 1480 series u-joint kits available from Tom's Differencial in California as well as other guys selling similar kits. they aren't cheap, but they are bullit proof. so what are you looking at installing motor wise?? Brian

 

[MaineShark]

I'm not sure about the '82 rear, but I think removing the IRS would definitely be excessive. That only tends to be done for cars making truly massive power. The most I can imagine being necessary would be to get the IRS out of an earlier Shark (say, find a wrecked big block), since that sort of torque was expected with the larger engines.

Joe

 

[82mystery]

hello brian,,thanks for your imput om my problem. i am planning on going with a 400 4bolt spayed billet caps,4340 crank, rod ect.,maybe canfield or afr heads with 2.05&1.6 ss anglecut valves., air gap intake with carb spacer and 870 avenger carb,big headers full length, solid roller cam with 108 c/l and matbe 625-630 lift with somewhere about 230 -240 duration. all items will be port matched and polished. i am trying to put together a hot street engine(and reliable) for some of these cobras that keep pesting me. have you ever ran a electric water pump on the street with any luck for duribilty? i have a art carr 700r4 with 3500 stall and 410 gears. i am hoping to reach mid 12 with this setup. what do you think? its been 25 years since i built something like this. how come none of the hotrod books that i have found has nothing on vettes.all i have been able to find is restoring them and to me what a waste of best sports car, for the money. thanks for everyones help on this.i am a little slow on this big computer. larry

 

[AKRAY4PLAY]

Larry,
i am running a 406 very similar to what you are looking at. the 700r4 is a little flakey when you start applying that much torque to them. besides, a 400 will make so much power down low that you don't want that deep of a first gear, it will just boil the tires to the rims. if you want to stay with the 700r4, swap to a 2500 stall converter, it will make your live a lot longer. i am running the AFR 210 race heads with 2.08/1.60 all CNC machined. i started with 74cc chambers and milled them to 71cc. the crank and rods are Eagle 4340 forged and rod length is 6.0". i am running a Crower cam with 248/256@.050 and .600 total lift with 110 lobe sep, full roller valve train. with 4.10 gears and 550hp you will be looking at the 11's if you can get traction. most of the hotrod books are geared to the in-line grocery getters because they are cheap to start with. most Vettes that are worth building up cost what most hotrod guys invest in their whole car. going real fast at most tracks, you can't run an IR Suspension because of safety rules. smart thinking because a broke halfshaft wipes out the suspension and makes for a dangerous ride. i stay away from electric water pumps, mechanical are much more reliable in my eyes. splayed mains are a must as are steam holes. i highly reccomend the AFR heads, they are the best hands down. i have a quite few ideas for 400 blocks and different builds, and would gladly share what i have learned with you, Brian

 

[cruisin-davey-g]

Larry,
i am running a 406 very similar to what you are looking at. the 700r4 is a little flakey when you start applying that much torque to them. besides, a 400 will make so much power down low that you don't want that deep of a first gear, it will just boil the tires to the rims. if you want to stay with the 700r4, swap to a 2500 stall converter, it will make your live a lot longer. i am running the AFR 210 race heads with 2.08/1.60 all CNC machined. i started with 74cc chambers and milled them to 71cc. the crank and rods are Eagle 4340 forged and rod length is 6.0". i am running a Crower cam with 248/256@.050 and .600 total lift with 110 lobe sep, full roller valve train. with 4.10 gears and 550hp you will be looking at the 11's if you can get traction. most of the hotrod books are geared to the in-line grocery getters because they are cheap to start with. most Vettes that are worth building up cost what most hotrod guys invest in their whole car. going real fast at most tracks, you can't run an IR Suspension because of safety rules. smart thinking because a broke halfshaft wipes out the suspension and makes for a dangerous ride. i stay away from electric water pumps, mechanical are much more reliable in my eyes. splayed mains are a must as are steam holes. i highly reccomend the AFR heads, they are the best hands down. i have a quite few ideas for 400 blocks and different builds, and would gladly share what i have learned with you, Brian

Larry: Your motor set-up is real "killer". I've got a question for you about the 400 SB. I've been told that the 4-bolts have a serious problem with the webbings stress cracking. I'm told that if you want a 4-bolt, take a 2-bolt & splay the caps, so you won't run into problems. Any truth to this? I was thinking of building one of these 400's. I've never done a 400 before, just all of the other SB's. I'm looking to do just a mild street set-up. Something to make just enough noise to intimidate the so-called wanna-be street racers (if you know what I mean). Thanx & good luck at the track.

Dave:

 

[groovyjay]

Hi there, no need to get rid of the IRS, it can take lot of abusing. My car for example makes 540hp/552tq and I have surely done my share of hard driving on drag strips and road courses. Unless you are aiming sub 10's on a 1/4 mileI'd say keep the stock IRS. There's loads of ways to improve it though. Here's few examples:

Start with Tom's stuff

http://www.tomsdifferentials.com/cat17.htm

Then get some carbon fibre half shafts and drive shaft from Van Steel

This is the company that makes them:

http://www.pstds.com/critical-link.cfm

And Van Steel sells them:

http://www.vansteel.com

But if you really want to get something wicked, get IRS Ford 9":

http://www.dutchmanms.com/1_indep9rears.html

Just for the record, I'm going get the carbonfibre drive and half shafts, so any one interested, let try to see if we can get some group discount!

 

[AKRAY4PLAY]

Dave,
you are correct about the mains on a 400. they only made the four bolt 400's from 70-74 i believe. the new GM performance block is a rocket block 400 with priority main oiling and spread pan rails that allow for a 4.125 stroke with no machining. a little machine work and the right rods and you can through a 4.25 crank in and make some real big diplacement. it even has splayed mains ready for assembly for about $2400. but using an old 400 with two bolt mains and main studs will support 500hp easily as long as you don't spin her past 6200rpm. lots of ways to build 400's and all make big power, Brian

 

[82mystery]

irs& 400 bld.

Hello brian ,joe and dave. sorry for the delay in getting back to you but had a lot of problems at work with equipment failure. dave, i agree with everything brian said on the 400 blk 2 bolt with studs for 500 to 550 hp. are you blding this or having someone do it ? whoever is doing this ,i would go ahead and spend the extra bucks on forged parts along with maybe some good port ect. work on the heads. joe thanks for your ideal on the big blk irs, that may be something that i will check about. well brain i save you till last. i like your bld on the 406,it looks like it would be a killer engine combo. i would appreciate any ideas on your 400 blds. the art carr 700r4 that i have is supposed to handle up to 900hp. thanks for the tip on using the 2500 instead of the 3500 stall. i thought maybe the 3500 would be too much for street. has anyone ever had any dealinf with speed-o-motive out of calif. they build some killer combos with really good prices but idon"t know about how well they do it. i am sorry about answering all of you so late as well as combining everything in one message but i am knew to this computer thing and wasnot sure on how to do them each seperate. thanks again for everyone imput i really appreciate it. thats what i like about this site because it save one so much trail error method and wondering of this would work. have a great day everyone. larry

 

[AKRAY4PLAY]

Larry,
speed-o-motive has a fairly good rep, they get low prices by volume and generic builds. most of the builds they have are 406 and 383 with 5.7 rods, cheap but the better way is with 6.0 rods. i have an engine builder that did the finish machine work and dyno'ed my motor. he lives right down the street from me and has a top of the line shop with all CNC machine tools. very classy operation, he used to build most of the big USAC midgets and some NASCAR engines when he lived down south. i have heard that he still builds and ships motors to his racing buddies, so i can check on prices for you. it will most likely be cheaper to have a local machine shop prep a block for you and assemble it yourself. if you give me some numbers to work with, i can start throwing some combos and prices your way. just need to know your budget, hp and torque figures to work with. rpm range would be nice also, but that is negociable later. i also have a parts guy down south that saved me a couple grand on engine parts alone, but then again i did not skimp on anything in my quest for duability. let us know what you want to do, Brian
ps. i would question that 900hp rating on a 700r4, the case has a tendency to twist above 500 hp because of the length. that is one reason that hard core guys still use the shorter two speed powergluides. i am not familiar with art carr, but i am leary of r4's in general.

 

[tscott9330]

Ok, So i have a dumb question. What is a splayed main? I assume by main you mean the main caps on the lower end.

Tom Scott

 

[82mystery]

splayed mains

tom. sorry for not getting back to you sooner but i have been out of town. splayed mains means that the outer bolts on a 4 bolt main are drilled and tapped at a angle versus of going at a 90 degree to the blk web. i have seen this done on a two bolt also making it into a 4 bolt . this adds a lot of strength to the mains. you can can also use a stud girdle, like on your valve, train that will a lot strength as well. either one should 500+ hp easily. larry

 

[82mystery]

brian, i wish i had found this site before my build but i have everything together except the heads and i in the processing of gettin the pro heads, alu, with full street porting as well as polishing. i hope to take to the dyno tuesday,3-20-03, and the truth will be know. i am in the process of checking on this wreck vette that will need a engine i know and if it turns out to useable i will give you shout if thats ok. i think it had a 377cu inch that came apart,crank broke and went thru blk, so if i get this i won't be using that 400 blk. i usually put about 5 or 6.5 big ones in the engine. larry

 

[AKRAY4PLAY]

you can build a great motor for 6 large. i would look at te AFR heads for the next one. they flow better out of the box than most ported heads. that makes the cost offset near nothing, and you can always port them in the future. a destroked 400 (377) is one hell of a revving engine with the right valve train. it would work very well in a stripped Vette with a manual tranny. just another thought for nibbling on, Brian