427 conversion

[Guest Zman525]

Hi i have the A rolling chassis of a 1972 240z and im going to obtain a 427 and i was wondering what i would need to do fabricating wise. I was thinking about putting in a roll cage and just chopping off the whole front end and doing it over. The top of the unibody and frame rails are gone anyways so they are being chopped out. Has anyone ever done this before ( refabricated the engine bay so its totally custom?) If so any input is helpful. Thanks for your time.

[Guest 73TPIZ]

Welcome aboard.

 

Check out the posts from 74 5.0L Z. His page is here.

 

http://forums.hybridz.org/member.php?u=7833

 

He was in an accident and totally rebuilt the front end out of tubular. That is some beautiful work he did on that Z.

 

Lots on here will fuss if you don't use the search function to answer specific questions you will definetly have over the next several months of working on your project (or years for lots of us).

 

If you search one word you are likely to get 30 pages of hits which is discouraging. Try quotes around each of 2 or more words with an and in between. I narrows the field greatly. SHELL WEIGHT got me 30 pages the other night but ' "shell" and "weight" ' got me one hit which is the one i was looking for. Try a search for "454" or "big block" and you may have some luck.

 

Again, welcome aboard and good luck with the project.

[Guest Zman525]

thanks alot. yah i kno im gunna catch some greef but i figured u guys could handle it... ive been a member of www.classiczcars.com for awhile now and i was toldi could get some nice reference here. Thanks for the help!

[dr_hunt]

Is that a ford 427 side oiler or a chevy 427?

[5foot2]

Is it a bbc 427, or a stroker sbc? There is no need to do anything radical to install either (assuming you have a solid car to start with). The bbc is a bit taller than the sbc so hood clearance is an issue. You'll want to mock it up with the oil pan, intake/carb and dist. setup you plan to use to get the motor as low and as far back as practical.

[dot]

Watch this.

http://www.ratsun.com/videos/mel1042003.mpg'>http://www.ratsun.com/videos/mel1042003.mpg

 

This is his sight.

http://www.ratsun.com/

[Michael]

The BBC conversion is a handful. I don’t want to insult the people who believe that it doesn’t require anything “radicalâ€, but suffice it to say that I couldn’t disagree more strongly! Weight and balance issues can be overcome, but they are not trivial. There is no analog to the JTR kit, though the Mark IV BBC and the Gen I SBC have the same mounting bolt pattern, and the same transmission bellhousing pattern. There are (or were ) some 5 or 6 big block Chevy Datsuns on this board, but to my knowledge all are either backhalved, tube-chassis, altered-firewall or some combination of the above. Mine retains the stock suspension and nominally the stock front end, but the firewall is relocated aft for better balance and more clearance, and there are a few reinforcement tubes here and there.

 

The BBC swap is worthwhile if you’re a BBC specialist and would like to carry that knowledge over to the Z world. Otherwise the safer bet is on a stroker SBC.

 

But like 5foot2 said, mock-up the engine installation and gauge for yourself whether the fit is acceptable or not, whether the headers hit the frame rails or not, whether the steering shaft clears or not, whether the crank pulley hits the steering rack, and so forth. Then worry about engine mounts – you’re almost guaranteed to have to mount off the frame rails, not off the steering crossmember (as most SBC’s mount). And then proceed to considerations of structural reinforcement. It isn’t strictly necessary to radically alter the engine compartment, for example by relocating the firewall aft, but it makes sense from an overall balanced-car (literally and figuratively) point of view.

 

Don’t hesitate to post specific questions if you have them. I don’t want to come across as excessively negative – but it’s better to forego a risky project than to go knee-deep and then capitulate.