FJ73 350 chev conversion help

[boy-c]

hey all,

i am in the middle of building up my 73 middy. at the moment i have pull the body off and fitted a 90 ute body on and custom tray. i have striped the engine bay read to drop the 350 in but before i do i was going to clean up the bay and paint it, so my question is do most conversion kits require me to massage the firewall? or are there better ones like marks that do not require it?

second question is i have fitter new spring and extended anti inversion shackles, that has given me a nice amount of lift but have also turned the diff up a little so i was thinking to re drill the springs and move the diff forward 50mm. i am wondering if this would affect the spring much in flex or strength? moving it forward as it would clear the 37s very nicely and i wouldn't have to trim the bottom of the guards.

[boy-c]

ok after doing more searching i have read that drilling the pack is bad option. but if you move it forward how do you locate the diff once you move forward as the diff locating bolts on the bottom of the diff wont sit into the holes in the springs or would you get the springs reset?....

[zukmeista]

Drill a new locating hole in the spring perch.

[sadam_husain]

yeah you'll have to do some minor firewall massaging but it'll probably be next to nothing if you've got a 2" bodylift in it, I did mine before I body lifted my truck and I only had to do a bit of massaging for the LH head, I just tapped it back with a club hammer and a piece of carpet and it came up ok with no bruising or hammer marks on the steel. We swapped over to an LS engine last year and had to go some massaging on both sides as the heads sit back about 50-60mm further.


as above as zukie said redrill the perches and u-bolt plates not the springs and you'll be fine. I did that to my 40 series when I put a set of 70 series springs in the front and the centre bolts were too far forward and i had to redrill the perches and u-bolt plates to shift the axle housing back about 60mm so the tierod and draglink didnt fowl on each other, this meant the perches and u-bolts clamped onto the curved part of the ome springs instead of the flat part but its given no problems and nothing moves or comes loose

[boy-c]

i wont be putting body lift in wont need it with the springs and the front diff forward bout 50mm i will clear my 37s pretty easy. so would that me more firewall massage? i am going to ring up marks to find out some info on the adapters, cause i am going to try and get a diesel box to put behind it instead of the 3F box i have.

[Fakey]

Wow Marty 3 posts since joining in 06 lol, you got that 75 out an about yet?

You will only get about 40mm further forward by redrilling the spring perches IIRC, I drilled mine 30mm to fit 35's an the tie rod an drag link got very cosy. I had 2" OME springs an 35"s on 10" rims an they scrubbed a little bit. ow much lift are you planning on running to fit 37"s?

I Put a 350sbc in my BJ74, but I custom made everything except the bellhousing. I mounted the engine with about 15-20mm of clearance between the rocker covers an the standard firewall. In this position the gear lever came thru the floor 50mm futher forward than it would normally, this didnt matter to me tho as I was converting to manual from the factory diesel auto

[sadam_husain]

Wow Marty 3 posts since joining in 06 lol, you got that 75 out an about yet?

yeah didnt even know I'd joined this site, yep been doing a fair bit of running around in my 75 recently, its come out pretty good nice and reliable and drives nice but shit its drinking gas I got 225km out of the first tank and this tanks looking like I might just get 300km out of it

[Fakey]

Haha I bet it chews thru some gas, mainly due to the skinny pedal getting a work out everytime ya take it out