TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Transmission & Drivetrain
  New Posts New Posts RSS Feed - 998 build research
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

998 build research
 Post Reply Post Reply Page  12>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
gremlinsteve View Drop Down
AMC Addicted
AMC Addicted


Joined: Dec/16/2008
Location: houston
Status: Offline
Points: 884 		Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlinsteve Quote  Post ReplyReply Direct Link To This Post Topic: 998 build research
    Posted: Apr/18/2018 at 12:00am
I'm trying to determine who builds a good 998 amc
I am going to maintain the trans that came in my gremlin
And it's soon to have a 500-520 hp 401 in it

So I am obviously interested in getting this transmission built to handle
And give me good performance

Any particular kits or parts I should be after?   No racing
Or burnouts.   It's a column shift car so no reverse manual v bodies
Back to Top
401jim View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jan/07/2012
Location: Brunswick,Ohio
Status: Offline
Points: 793 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 401jim Quote  Post ReplyReply Direct Link To This Post Posted: Apr/22/2018 at 10:01am
You are going to PAY A LOT of MONEY to make that trans last. My friend had one back a few years ago and was constantly back to the trans builder for repairs. I will not post the trans company that did it cause it is not fair to them or you. It is a national brand name company. If you are looking for that margin of h.p. to the rear wheels then I hope you have a big wallet. Jim
Back to Top
purple72Gremlin View Drop Down
AMC Addicted
AMC Addicted
Avatar
Charter Member

Joined: Jul/01/2007
Location: Illinois
Status: Offline
Points: 16611 		Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Apr/22/2018 at 4:35pm
Originally posted by 401jim 401jim wrote:

You are going to PAY A LOT of MONEY to make that trans last. My friend had one back a few years ago and was constantly back to the trans builder for repairs. I will not post the trans company that did it cause it is not fair to them or you. It is a national brand name company. If you are looking for that margin of h.p. to the rear wheels then I hope you have a big wallet. Jim
pretty much my opinion too. That's why I prefer a 727 for street driving a high performance car. Durability. Now for a drag car, that's a whole different ball game....but this is just my opinion. And if you dont agree...fine....
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7544 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Apr/22/2018 at 10:53pm
is there a particular reason for the small transmission behind the large engine? 
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com
Back to Top
purple72Gremlin View Drop Down
AMC Addicted
AMC Addicted
Avatar
Charter Member

Joined: Jul/01/2007
Location: Illinois
Status: Offline
Points: 16611 		Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Apr/22/2018 at 11:15pm
Originally posted by tomj tomj wrote:

is there a particular reason for the small transmission behind the large engine? 
The smaller transmissions take less HP to drive them. and the 727 has that one big heavy drum which has exploded in drag racing...... 
Back to Top
1970390amx View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/11/2008
Location: colorado
Status: Offline
Points: 3314 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Apr/23/2018 at 12:23am
In a street car i dont believe you will break the trans with 500HP, you will blow the tires off before the trans breaks. Performance rebuild kits are available I would use one and make sure the front and rear drum use all the clutches in the kit. Some transmissions have drums that will hold one less clutch than others. If it is a lockup transmission I would get rid of that. A lockup input shaft is hollow. Make sure it have the the planet set with the lower first gear ratio. Shift kit is a no brainer I would use a trans go kit. The throttle linkage needs to be adjusted to max pressure. The hard part would be if your shift points are not correct with the TV adjusted to max pressure governor modifications would be needed to fix shift points. A shift point that is a little low is better than one that is to high. If they are to high a driver has a tendency to lift on the throttle to get it to shift. Just my opinion.
1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box
Back to Top
amx2bfast View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Aug/07/2013
Location: middlesex nc
Status: Offline
Points: 217 		Post Options Post Options   Thanks (0) Thanks(0)   Quote amx2bfast Quote  Post ReplyReply Direct Link To This Post Posted: Apr/23/2018 at 8:22am
I had a 998 built by Turbo Action in Florida . I did have to send a case to them. Beat on it for about 8 years before I had any issues. They sell all the parts you need to do it yourself. They were the only ones at the time that would build one to handle 600 hp. Was very happy with it. Now I buy the parts to do it myself.
1975 gremlin
1973 javelin
1976 pacer wagon
Back to Top
one bad rambler View Drop Down
AMC Addicted
AMC Addicted


Joined: Jan/09/2008
Location: On The Island
Status: Offline
Points: 2007 		Post Options Post Options   Thanks (0) Thanks(0)   Quote one bad rambler Quote  Post ReplyReply Direct Link To This Post Posted: Apr/24/2018 at 9:40pm
Originally posted by purple72Gremlin purple72Gremlin wrote:

Originally posted by tomj tomj wrote:

is there a particular reason for the small transmission behind the large engine? 
The smaller transmissions take less HP to drive them. and the 727 has that one big heavy drum which has exploded in drag racing...... 
I have been putting more than 500hp through my 727 for 14 years know with an occasional 150 shot...dollar for dollar a 727 is the way to go for 500hp...we run a 715cu with over 2,000hp through a power guide but you have to get a 2nd mortgage on your house to do it.... 
68 AMX 390 4 Speed,68 American,64 American 2 Door Wagon Altered Wheelbase,78 Concord Build 360,727,8.8
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7544 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Apr/24/2018 at 9:57pm
interesting. i didn't realize the 998 was that rugged. i stand corrected.

the dumb ole 904 has been a reliable beast, IMHO. probably should not have been surprised the 998 is so good.
1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com
Back to Top
Thikstik View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/20/2008
Location: Alabama
Status: Offline
Points: 1327 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Thikstik Quote  Post ReplyReply Direct Link To This Post Posted: Apr/25/2018 at 2:10am
Originally posted by 1970390amx 1970390amx wrote:

In a street car i dont believe you will break the trans with 500HP, you will blow the tires off before the trans breaks. Performance rebuild kits are available I would use one and make sure the front and rear drum use all the clutches in the kit. Some transmissions have drums that will hold one less clutch than others. If it is a lockup transmission I would get rid of that. A lockup input shaft is hollow. Make sure it have the the planet set with the lower first gear ratio. Shift kit is a no brainer I would use a trans go kit. The throttle linkage needs to be adjusted to max pressure. The hard part would be if your shift points are not correct with the TV adjusted to max pressure governor modifications would be needed to fix shift points. A shift point that is a little low is better than one that is to high. If they are to high a driver has a tendency to lift on the throttle to get it to shift. Just my opinion.
Agreed with all he said except for the low gearset.  The low gearset will load the trans planet more as it is a lever having to do heavier lifting and also causing a a bigger gear-split that is going to slow your trap speed.  Recall the phrase "Close ratio"?  you dont want a large gear split.  I dont recall the exact specifics of 904 VS 998. Do know that AMC lowered first gear to accomadate smogger rear axle ratios. I do know the 998 had an extra clutch...dont recall for which gear. I do see a note i made in my 998/727 where i wrote: the AMC 304 keeps the 4 disc front frictions but has 4 frictions in the rear whereas the 258  uses 2 rear frictions.  Also, I added another friction to front clutch pack. i'd not be too scared of a 9o4 turned into a 998 with clean fluid and Lubeguard and a radiator cooler running in series with an air to air cooler.  Dexron 6-7 is necter.  Its extremely superior in the GM trans...im a bit embarassed to admit, I dont know if its ok to use in our Mopar transes. Ever seen a Grand National trans (200R4)?  Its pubic with a smaller input shaft thats hollow lol.  The 904/998 is a gem that is no weak player.  If it breaks, its soo cheap/easy to fix and most likely will not break its hard parts. SMRTransmissions in Canada is who i consulted ahile back when i built my trans.  I just wish it had a 4th gear.  Hello A 500.
75 gremlin x, jeep 4.0 headed 258,
264H Cliff cam, intake,header. 390 holley. I want a 282 VAM motor!

AC/PS/PDB.

72 AMX , 304 2bbl, 3speed, now disks...probably will sell, want an automatic /AC.
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.203 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or