question on the 7.5 rear

jays306LX · 06-04-2001, 08:01 PM

i was just wandering if anyone might have a guess as to what gears a 7.5 would have in it coming from a auto 4 banger car? i have to use this rear till i can muster the money up to get my 8.8.. with my mods i hope this thing will hold up i have everything for my 8.8 i just the need the darn thing plus i figure while i am breaking the car in i wont be getting on it real hard.. thanx

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84 lx coupe 75 truck block .030 over trw 10-1 pistons comp magnum 280h .512 .512 lift with 230 duration.. early casting heads 1.94 1.60 valves 58 cc chambers harland sharp rockers 1.6 air gap intake with mild porting holley 600 vac seconderies 2 inch open spacer. built man c-4 with PI 2800 sthall 8.8 strange spool 3.73's moser 31 spline still building the rest going for high to mid 11's

06-07-2001, 10:00 PM

I think they are 3.45 or something in that neighborhood. On a friends (87LX)4-8 swap, he ran the 7.5 until he got his 8.8 and ran an 8.44 in the 1/8 mile. He held up the whole time until he got his 8.8 with 4.10's...

------------------
Mike

Sold my 88GT Aug Y2K

Just got T-top 86GT 11-18-2000

jays306LX · 06-07-2001, 11:03 PM

thanks i have also heard that it should hold up if not gives me even more of a reason to get that 8.8 put in lol thanx again

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84 lx coupe 75 truck block .030 over trw 10-1 pistons comp magnum 280h .512 .512 lift with 230 duration.. early casting heads 1.94 1.60 valves 58 cc chambers harland sharp rockers 1.6 air gap intake with mild porting holley 600 vac seconderies 2 inch open spacer. built man c-4 with PI 2800 sthall 8.8 strange spool 3.73's moser 31 spline still building the rest going for high to mid 11's

oldman · 06-09-2001, 12:28 AM

Don't talk yourself into thinking the 7.5 will last very long. I happened to have a couple of em so that's what I used behing a Cleveland. Each one lasted about 5 months before making clunking noises once in a while. Both let go with a really loud BANG. Just got a new (79) LX that happened to have an 8.8 in it. hopefully it will take everything the new cleveland will throw at it. By the way, the 7.5 out of the 82 GT was a 3:08 while the 4 banger rear wsa 3:27 I think.

90dpscoupe · 06-09-2001, 03:54 AM

Oldman, i think u just answered my question, my friends 85 coupe, was a ex-4banger, and we are not sure if its an 8.8 or 7.5, but i was gonna ask about a "clunking" noise we hear? it does have e.t. streets on the back, and i was sure those stickies would break a 7.5 pretty quick? also has alum d/s, what you think? how can i tell?...thnx

------------------
90 lx coupe: 175k miles, steeda water pump pully, hurst shifter, Mac cold air fenderwell, accel supercoil, ADS chip, aluminum D/S, Black magic fan, 3.27grs.
Best time: 13.9116(on 225/60/15 firehawks)
Best mph: 98.17
Best 60': 1.9607

next mods: subframes, mac h-pipe

red82gt · 06-09-2001, 04:03 PM

The 7.5 has a straight top and bottom edge on the diff. cover and the sides are curved, all 4 edges of the 8.8 cover are the same. There should be a tag on one of the bolts holding the cover on the rear that will have 7 5(the size of the ring gear) and the gear ratio after, 308 or whatever it may be.

06-04-2001, 08:01 PM	#1
jays306LX Registered Member Join Date: Jul 2000 Location: knoxville,tenn,usa Posts: 163	question on the 7.5 rear i was just wandering if anyone might have a guess as to what gears a 7.5 would have in it coming from a auto 4 banger car? i have to use this rear till i can muster the money up to get my 8.8.. with my mods i hope this thing will hold up i have everything for my 8.8 i just the need the darn thing plus i figure while i am breaking the car in i wont be getting on it real hard.. thanx ------------------ 84 lx coupe 75 truck block .030 over trw 10-1 pistons comp magnum 280h .512 .512 lift with 230 duration.. early casting heads 1.94 1.60 valves 58 cc chambers harland sharp rockers 1.6 air gap intake with mild porting holley 600 vac seconderies 2 inch open spacer. built man c-4 with PI 2800 sthall 8.8 strange spool 3.73's moser 31 spline still building the rest going for high to mid 11's

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06-07-2001, 10:00 PM	#2
Myke_y2k Guest Posts: n/a	I think they are 3.45 or something in that neighborhood. On a friends (87LX)4-8 swap, he ran the 7.5 until he got his 8.8 and ran an 8.44 in the 1/8 mile. He held up the whole time until he got his 8.8 with 4.10's... ------------------ Mike Sold my 88GT Aug Y2K Just got T-top 86GT 11-18-2000

06-07-2001, 11:03 PM	#3
jays306LX Registered Member Join Date: Jul 2000 Location: knoxville,tenn,usa Posts: 163	thanks i have also heard that it should hold up if not gives me even more of a reason to get that 8.8 put in lol thanx again ------------------ 84 lx coupe 75 truck block .030 over trw 10-1 pistons comp magnum 280h .512 .512 lift with 230 duration.. early casting heads 1.94 1.60 valves 58 cc chambers harland sharp rockers 1.6 air gap intake with mild porting holley 600 vac seconderies 2 inch open spacer. built man c-4 with PI 2800 sthall 8.8 strange spool 3.73's moser 31 spline still building the rest going for high to mid 11's

06-09-2001, 12:28 AM	#4
oldman Registered Member Join Date: May 2001 Location: Amarillo, Texas, 79107 Posts: 78	Don't talk yourself into thinking the 7.5 will last very long. I happened to have a couple of em so that's what I used behing a Cleveland. Each one lasted about 5 months before making clunking noises once in a while. Both let go with a really loud BANG. Just got a new (79) LX that happened to have an 8.8 in it. hopefully it will take everything the new cleveland will throw at it. By the way, the 7.5 out of the 82 GT was a 3:08 while the 4 banger rear wsa 3:27 I think.

06-09-2001, 03:54 AM	#5
90dpscoupe Registered Member Join Date: Jun 2000 Location: sanantonio, Tx, usa Posts: 1,407	Oldman, i think u just answered my question, my friends 85 coupe, was a ex-4banger, and we are not sure if its an 8.8 or 7.5, but i was gonna ask about a "clunking" noise we hear? it does have e.t. streets on the back, and i was sure those stickies would break a 7.5 pretty quick? also has alum d/s, what you think? how can i tell?...thnx ------------------ 90 lx coupe: 175k miles, steeda water pump pully, hurst shifter, Mac cold air fenderwell, accel supercoil, ADS chip, aluminum D/S, Black magic fan, 3.27grs. Best time: 13.9116(on 225/60/15 firehawks) Best mph: 98.17 Best 60': 1.9607 next mods: subframes, mac h-pipe

06-09-2001, 04:03 PM	#6
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	The 7.5 has a straight top and bottom edge on the diff. cover and the sides are curved, all 4 edges of the 8.8 cover are the same. There should be a tag on one of the bolts holding the cover on the rear that will have 7 5(the size of the ring gear) and the gear ratio after, 308 or whatever it may be.