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yamahondarider

Big Block swap

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Has anyone used the JTR small block mount kit for a big block chevy?  In theory it should work, BBC has the same mounts and their the same distance from the bellhousing, and use the same bellhousing as a SBC. I've been searching for a couple weeks on various sites and youtube, using google's reverse image search with pics I found of BBC's in Z's hoping to find a build thread, so far I've found a few builds with dead pictures, and one that still has pictures but they aren't too great. There are a handful of pictures floating around of the motors sitting in these cars, the heads clear fine, but I'm trying to figure out what exhausts people are using. Maybe a stock manifold from? If theres anyone here who's done a BBC swap I'd like to pick your brain and see how you did it. 

 

I'm very aware this throws off the 280z's weight balance and makes it nose heavy. I hope to offset that a bit by removing the A/C system and moving the battery to the trunk, I have no front bumper either. However I have no plans to autocross this car, just cruise and light up the tires, and a little stoplight to stoplight drags so I'm not worried about weight balance or hooking up (that'd just tear up the U-joins and R200 diff anyway). 

 

I did search plenty, and absorbed a lot of info, I'm just hoping I can hear from someone whos done the swap and find out if the JTR SBC kit would mount a 454 in a 280Z and what you guys are doing for exhausts. Other than that, I've got the bases covered. just need to fill in the gap a bit. 

 

Heres some eye candy I've found on the interwebs, 

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Ive done this swap a few times.

 

The manifold is really close to the steering shaft. You will need to make custom headers if my memory serves me. The stock manifolds nearly fit if you can clear the steering shaft. With a JTR mount kit they probably wont though. The JTR kit will push that engine back and down as far as possible. Also the pan will hang a little low.

 

Ray

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It'll be a really tight squeeze and the extra weight up front will affect drive ability.  

 

As mentioned above the oil pan will hang low and you'll need custom headers.

 

In my opinion you should just get a 400 block and make a 427 or 434 you'll save yourself ALOT of heartache. 

 

Read this book, it is very informative http://www.amazon.com/Build-Big-Inch-Chevy-Blocks-Design/dp/1934709662

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Andy flagg has a Cadillac lump in his 280z.. that seemed really tight!   it is set up as a drag car so it does not need to steer. but lets say i had an inspiring drive around the block in that car.. the torque was simply brutal.

So your goal of cruising and lightning up the tires should be easy.. the BB Z I drove in felt like it wanted to lift its nose!!!!

 

so please keep us updated!

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I set a 454 down into mine at one point using a copy of the scarab mounts. It had the stock intake with a quadrajet. With the stock air cleaner it all fit under the stock hood. With those mounts the headers that came with the big block also fit with a small dent for the steering shaft. I have no idea what brand they were but the set up was in a 1973 Chevy two wheel drive truck. Decided it would handle like crap so went with an aluminum headed 388 small block that with an Edelbrock Performer RPM intake will not fit under my cowl induction hood with the air cleaner on. I have since got the JTR mounts. Engine fits but know I cant use my full length Hooker Headers. I have not searched lately but last I looked only some small tube shorty headers fit with the JTR mounts which will seriously choke the performance of my engine. I am seriously considering widening the frame rail area centering the engine and then building headers.

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PM Michael, he has a big block Z - http://forums.hybridz.org/user/11-michael/

Chiming in - albeit some 2-3 years too late.  Has yamahondarider pursued this swap?  It seems that with every passing year, the "classic" Chevy V8, whether small-block or big-block, recedes into obsolescence, ceding ground to the LS-series.  It would be - how shall I phrase it? - nostalgic, to see another big block swap into an S30.  Mine sort-of runs... it receives an occasional engine-start in anger, and jog up and down my driveway.  But it's in more or less permanent state of hibernation.

 

My recommendation to yamahondarider - and to others considering this swap - is to pursue it if and only if you're intimately familiar with the big block Chevy.  If it's your engine of choice, then use it.  If it's one competing option among many, well, today there are more appealing alternatives.  In my case, the firewall is set back, and the engine mounts to reinforcements of the frame rails.  I use a Hamburger low-profile oil pan, which terminates just above the lowest point of the transmission bellhousing.  With an Edelbrock Performer - RPM intake manifold and a 4" air cleaner, conventional hood clearance is not possible. I built a fiberglass hood with an indentation around the perimeter of the air-cleaner, which is crude but effective.  Hooker block-hugger headers fit, with some cutting and welding.  Diagonals between the front strut towers and the dash-bar (so, penetrating the firewall) make engine removal interesting; it requires removing the starter and oil-filter, and dexterously using a leveling-bar on the engine hoist.  The distributor is about 3" ahead of the windshield, and the driveshaft is about 14" long... that's how much engine setback there is.

 

Good luck to all, and here's hoping to see more traditional V8s in our Zs!

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