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big block does fit


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okay I have had my 280z for about a year now I finally got my hands on a 454 and a turbo 400 trans everthing works fine. I tested it in a 1975 chevy 1 ton and got it to peel through 1st and 2nd. well i need to know if the motor mounts are the same. they look the same in the pickup that i got the 454 out of, and my friend has the same year with a 350 in it. If it is then I can just order mounts for a small block. does anyone have pictures of the motor mounts or a diagram or experence. thanks , by the way a big block will fit fine with no cuting.

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hmm good idea, I thought that small blocks and big blocks shared the same mounts just you have to turn them upside down, or is that ford? i can't remember but Im sure someone else who knows chevys inside and out will know for sure... very good idea tho!! I may build a bigblock for my Z nextgo round!!

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You might want to check your cross member and steering arm and rearend.That is MEGA TORQUE and alot of torsion. You will probly also lose the balance of the Z.Like front heavy.Im in NO WAY even close to the knowledge Of some of these guru's on this site but check it out first.I have saved ALOT of money and skin with all the free pointers these guys humbly give.Keep the site up on your progress.I for one hope you do it.Good luck.

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I do remember a 454 in a z a while back it was a video and it had that vortec supercharger on it for a carb, i remember them doing doughnuts in it and stomping it like at 30mph and just roasting off the tires.. but it was like a year ago when i seen the vid.

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Gen I SBC and Mark IV BBC have the same engine mounts and the same bellhousing bolt pattern.

 

A BBC longblock will fit in the 240-280Z without any “cuttingâ€, but be aware of complications in fitting the exhaust tract, in how far the oil pan hangs down (especially if you’re using the 9â€-deep truck oil pan) and how far the air cleaner sticks out (especially with a Performer RPM-type manifold).

 

The blown 454 mentioned above has, I believe, changed hands, and now sports a SBC. There’s still a handful of BBC Z’s on this site. Mine has some sheet-metal mods, including a setback firewall location and some chassis reinforcement, but the rear end is stock (R200). Other BBC Z’s are back-halved.

 

Bottom line – yes, it can be done, and no, the weight/balance issue isn’t necessarily a showstopper, but there definitely are complications. It is NOT as simple as the JTR SBC swap. And while the JTR-type SBC setback plates might work, it would be better to mount the motor to the frame rails (with suitable reinforcement).

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well said MICHAEL

 

sbc and bbc engine mounts are NOT identical but THEY WILL USUALLY BOLT UP AND WORK interchangable in MANY applications

 

yeah, Ill second the concerns about the oil pan clearance under the car/cross members ETC. and hood clearance, yeah it can be made to work but not as easily as a sbc, but then its SO MUCH MORE IMPRESSIVE! LOOKING, AND HAS A GOOD DEAL MORE POTENTIAL, BUT ID SURE INSTALL A FULL ROLL CAGE AND TUB THE REAR, THE POTENTIAL TO TWIST THE CAR UP OVER TIME INCREASES A GOOD DEAL

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so they are not the same but will usally bolt up, well all I have is a big block or I would use a small block. next thing I have a th400 trans, do they make mounts that work? the oil pan doesnt hang down at all I think it is a differnt pan.well at least I know it has been done. all I plan on doing to the motor is new gaskets and a aftermarket carb.last and not least is there any where I can get gears so I don't peel through all 3 gears. thanks

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well said MICHAEL

 

sbc and bbc engine mounts are NOT identical but THEY WILL USUALLY BOLT UP AND WORK interchangable in MANY applications

 

yeah' date=' Ill second the concerns about the oil pan clearance under the car/cross members ETC. and hood clearance, yeah it can be made to work but not as easily as a sbc, but then its SO MUCH MORE IMPRESSIVE! LOOKING, AND HAS A GOOD DEAL MORE POTENTIAL, BUT ID SURE INSTALL A FULL ROLL CAGE AND TUB THE REAR, THE POTENTIAL TO TWIST THE CAR UP OVER TIME INCREASES A GOOD DEAL[/quote']

 

SBC and BBC's DO actually have identical mounting locations. This is why you can bolt a BBC in place of a SBC, using the same mounts on Chevy cars and trucks.

SOME models used a heavy duty mounting style for the BBC's, BUT often the hi-po SBC's used the exact same mounts, i.e. 1970 LT1 Z/28's and SS 396 cars.

So the BBC would typically bolt in place of a SBC, only worry would be space available.

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The gearing issue will be important down the line, but I wouldn’t make it a priority while you’re still trying to install the motor. Once the motor is installed and the driveline connected, and that mythical first drive is under your belt, you may find that your original specs for the motor will undergo considerable changes. As the power band and other specs change, so will the ideal gear ratio.

 

My combo also has a non-overdrive transmission, though it’s a stick-shift (Doug Nash 5-speed, with 1:1 5th). This was a good choice 6 years ago, because aftermarket blowproof bellhousings for the T56 were not available, and beefed-up T5’s weren’t around. I could have used a Tremec or a Richmond 6-speed, but the 6th gear in the Richmond unit is reputedly quite week, while the Tremec has a very notchy shift mechanism. Besides, I got a good deal on a used Doug Nash unit ($750 with the shifter). At some point I might do a rear end swap, with for example a numerically lower-ratio R230.

 

The TH400 might be a tight fit in the transmission tunnel. Are you open to cutting up the sheet metal and welding in patches?

 

Now here’s a question for the broader community: why is it such a common concern, especially for new members to say that they’ve got their bodywork and frame sorted out, their engine selected or in some cases already assembled, and even the transmission done,… but they’re worried about the rear end? I say, build the engine, build the car, take it to the track, and if your 60-ft times are disappointing or the rear-end grenades, THEN worry about replacing it! Broken stock parts are easy to replace. Fabbing new custom parts is what’s difficult!

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  • 3 months later...

yes i am here i have to use the schools computers to get on the internet and well the project is on hold and i am thinking about scraping the whole thing and going with a 87 305 with roller lifters and puting vortec heads and fuel injection on it with a 6 speed. since gas is going to be so high but i recently joined the navy for five years as a jet engine mechanic and will be getting 4,000.00 bouns as soon as i make it through basic so now i am waiting for the money to finish it.

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Project BBZ, any updates on your progress? You cardomain page concludes right at the point where you're about to commence the actual swap....

 

I'd be especially interested in seeing your solution to the frame rail/exhaust header (Hooker 1.75" block headers, right?) interference problem on the passenger side. Did the air cleaner clear the stock hood?

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Doesn't look like I will fit everything under the stock hood, so a MSA cowl hood maybe in order.

 

I still haven't verified if the headers will work or not. I decided to go ahead and do everything right and the TH350 is getting BUILT and a chrome-moly 10 point roll cage is getting installed in the Spring. Otherwise everything was good to go, but the wife got laid off yesterday so now the car is on hold....again.

 

I also need to buy another digital camera, the last one was lost in the move from Hanford to Bakersfield last May. The move itself also put the car on hold, if its not one thing its another.....

 

No worries guys, I'll keep you posted.

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Cable,

My car is coming together from a logistics standpoint, I have about everything gathered to build it, kinda hard to do from Iraq though :)

 

Final setup is gonna be the 400 SBC with TF 23 heads, solid cam 246 at .050 Lunati, Eagle rotating assembly, Air Gap, Demon 800.

I'm still trying to decide whether to use the Th350 with 2600-2800 converter or the 200-4R with about the same.

 

However,

I need a differential. Email me at jakeshoe@hotmail.com if you still have an extra and want to sell.

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