Ousted AMC V-8

Jp Magazine - - Your Jeep -

I have an ’81 CJ-7 with a car­bu­reted AMC 360 in it. It has a Ford T-18 man­ual trans­mis­sion, Dana 300 trans­fer case, and Dy­na­trac axles front and rear. It rolls on 37-inch Bog­gers and is beat on reg­u­larly. The AMC 360 is fi­nally tired. I looked into re­build­ing it for 400 hp, but the cost is kind of ridicu­lous for this Jeep. The AMC mo­tor al­ways had plenty of torque, but it was gut­less. Also, pretty much all of the ac­ces­sories on the front of the en­gine are worn out. At this point, I’m kind of done with the AMC en­gine and I’m not a Jeep purist. A friend is prac­ti­cally giv­ing away a com­plete Chevy 350 V-8 with all of the ac­ces­sories. How vi­able is this swap, and what parts would you use? Dustin Ewing

Via email

The AMC V-8s are well known for hav­ing an in­cred­i­ble amount of off-idle torque, mak­ing them great off-road en­gines, es­pe­cially at slow speeds. AMC V-8s are also well known for be­ing sig­nif­i­cantly more ex­pen­sive to re­build and hop up than the more com­mon GM V-8. Hav­ing said all that, an en­gine re­build is al­most al­ways less ex­pen­sive than an en­gine swap, but it’s not al­ways more prac­ti­cal, es­pe­cially in the long haul over sev­eral decades. In your case, you can pur­chase a stock re­built AMC 360 long-block from com­pa­nies such as ATK (atkvege.com) for around $2,700. A com­pa­ra­ble GM 350 long-block is about $1,000 less. Given that it sounds like you have your hands on a com­plete, in­ex­pen­sive GM en­gine in good shape and that you al­ready have your mind made up, you should sell the com­plete and still-run­ning AMC 360 to re­coup some of the costs of your GM V-8 swap. There are likely plenty of Jeep purists around look­ing for a good AMC 360 core to re­build. Good cores are not plen­ti­ful, and new en­gines have not been man­u­fac­tured in more than 25 years.

It’s for­tu­nate that you have the Ford T-18. This is prob­a­bly one of the most adapt­able man­ual trans­mis­sions avail­able. It can be eas­ily mar­ried to most pop­u­lar en­gines and trans­fer cases. How­ever, the Jeep ver­sion of the T-18 was avail­able with many dif­fer­ent length in­put shafts, sev­eral of which are com­pletely un­us­able when do­ing an en­gine swap in a short-wheel­base Jeep. Ad­vance Adapters (ad­vanceadapters.com) of­fers a 360-de­gree bell­hous­ing kit that will mate the GM 350 to your Ford T-18 (part num­ber 712549). The kit in­cludes a bell­hous­ing, dust cover plate, GM re­lease lever, GM throwout lever spring clip, ball pivot, pilot bush­ing, and the nec­es­sary hard­ware. This alu­minum bell­hous­ing is also drilled for the ’77-’79 Jeep T-18 trans­mis­sions that have a 2-inch-long pilot tip. A high-pro­file GM 11-inch di­aphragm-type clutch assem­bly is rec­om­mended for this bell­hous­ing. Cen­ter­force (cen­ter­force.com) part num­ber CF165552 works well. The in­cluded ball pivot and clutch re­lease arm are de­signed for a lo­ca­tion that is lim­ited to only the high-di­aphragm–type clutch. This larger 11-inch clutch assem­bly will re­quire the use of the 168-tooth GM fly­wheel. Ford

T-18 in­put shafts are nor­mally 11⁄16 -inch di­am­e­ter with 10 splines, which will re­quire the use of a Cen­ter­force clutch disc (part num­ber 281226) or equiv­a­lent. A Cen­ter­force throwout bear­ing (part num­ber N1714) fin­ishes out the clutch assem­bly. Your stock CJ-7 slave cylin­der and bracket can be re­tained and adapted to the new bell­hous­ing and GM clutch re­lease arm.

Ad­vance Adapters of­fers both weld-in (part num­ber 713007) and bolt-in (part

num­ber 713089) ad­justable mo­tor mounts for your CJ-7. The weld-in mounts are gen­er­ally a bet­ter choice for a Jeep that is used hard off-road. Both mount styles fea­ture mas­sive 5⁄8 -inch through bolts with iso­la­tors that will pretty much put an end to rub­ber mo­tor mount fail­ures.

No­vak Con­ver­sions (no­vak-adapt.com) takes a dif­fer­ent ap­proach when adapt­ing the Ford T-18 to a GM V-8. The com­pany re­tains the GM bell­hous­ing and mates it to the Ford trans­mis­sion with a few sim­ple and cost-sav­ing mod­i­fi­ca­tions. This gives you the abil­ity to use most GM bell­hous­ings, in­clud­ing full-cir­cle or open-bot­tom types. No­vak Con­ver­sions also of­fers ad­justable weld-in mo­tor mounts to se­cure your GM en­gine to the Jeep CJ frame.

As for cool­ing, you’ll need a new ra­di­a­tor with the proper in­let and out­let lo­ca­tions. For­tu­nately, the pop­u­lar­ity of the CJ-7 has led to the avail­abil­ity of nu­mer­ous af­ter­mar­ket ra­di­a­tors with GM V-8 in­lets and out­lets. Bolt-in GM V-8 con­ver­sion ra­di­a­tors are avail­able from com­pa­nies such as Ad­vance Adapters, Cham­pion Cool­ing (cham­pi­oncool­ing.com), Sum­mit Rac­ing (sum­mi­trac­ing.com), Ra­di­a­tor Ex­press (ra­di­a­tor­ex­press.com), and many oth­ers.

You may be able to keep the trans­mis­sion and trans­fer case where they are cur­rently lo­cated, which will sim­plify your en­gine swap and re­duce costs by not re­quir­ing drive­shaft mod­i­fi­ca­tions. The key ar­eas to make sure you have enough clear­ance will be be­tween the rear-mounted GM dis­trib­u­tor and the fire­wall, as well as around the en­gine, ex­haust, and ac­ces­sory group clear­ance near the fac­tory CJ-7 steer­ing shaft. If space is lim­ited or there is con­tact be­tween the com­po­nents, you’ll have to eval­u­ate the op­tions of mod­i­fy­ing these ar­eas or sim­ply move the trans­mis­sion and trans­fer case to ac­com­mo­date them.

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