TBI, smoke and hesitation

[superbuickguy]

usually they rust there... though the one in my fj40 was the classic orange-antifreeze-they-never-changed-it-it-became-mud issue...

nice thing about a BBC, change the injector body and the computer and your wiring harness stays put along with your distributor.

 

[ktmoutfront]

@mrk5 just did a 454 swap.

 

[mrk5]

I am still in the process of the swap, but I decided on Holley Sniper instead of factory TBI. As stated, you can use the 350TBI harness but you'll need the 454 throttle body with adapter and a different chip in the ECM. If I remember right, Brian, you have a 465 trans so you don't have to worry about transmission cables like a 700r4.

 

[ktmoutfront]

I am still in the process of the swap, but I decided on Holley Sniper instead of factory TBI. As stated, you can use the 350TBI harness but you'll need the 454 throttle body with adapter and a different chip in the ECM. If I remember right, Brian, you have a 465 trans so you don't have to worry about transmission cables like a 700r4.

You need to go to your thread and loadcthe video of your truck running.

 

[bp71k5]

I am still in the process of the swap, but I decided on Holley Sniper instead of factory TBI. As stated, you can use the 350TBI harness but you'll need the 454 throttle body with adapter and a different chip in the ECM. If I remember right, Brian, you have a 465 trans so you don't have to worry about transmission cables like a 700r4.

That's one thing that makes the 454 tempting, as long as it fits, I don't have to mess with too much other stuff. My concern is that my current motor is moved forward ~3" or so and I'm wondering if the big block would crash into my fans. I could move the motor back, but driveshafts....

 

[superbuickguy]

it would actually run fine without the new computer. A hot-rodding trick for 350s is to use a 454 TBI when you swap Vortec heads onto a ramp-head motor. That said, had I planned my build before i did it, I probably would have gone with any of the 4 barrel tbi systems available now. I save some money going the way I did on my '40 - but not enough that I'd be proud of the amount.

 

[ktmoutfront]

Also, the 454 is longer as measured from the motor mounts forward. If yours is forward already, it might be an issue.

 

[mrk5]

That's one thing that makes the 454 tempting, as long as it fits, I don't have to mess with too much other stuff. My concern is that my current motor is moved forward ~3" or so and I'm wondering if the big block would crash into my fans. I could move the motor back, but driveshafts....

Also, the 454 is longer as measured from the motor mounts forward. If yours is forward already, it might be an issue.

Yes, the motor is longer from the motor mounts forward. I would guess about 2 or 3 inches. There's probably good numbers somewhere on the interwebs.

 

[bp71k5]

Yes, the motor is longer from the motor mounts forward. I would guess about 2 or 3 inches. There's probably good numbers somewhere on the interwebs.

Looking like even a longer 454 saves me a bunch of expense and hassle even if I have to move the motor back a bit. 8.1 has same hassles and extra problems like radiator, ECM, exhaust, drivelines, and not as common aftermarket support. I'll be digging through your thread for sure. Finding the right donor would be first order of business.

 

[mrk5]

Seems like another member did a 454 swap last year with factory TBI as well.

 

[superbuickguy]

Years ago, I thought seriously about putting a BBC in a S-10 Blazer. This is what I found from that. The BBC is longer, but it gains part of its length from the transmission side (the lip to the transmission is shorter), it is, with a short pump, less then an inch difference front to back. Motor mount to the transmission flange, the BBC and the SBC are the same, transmission bolt pattern (as everyone knows) is the same. The largest difference and what killed it for me in the s-10 is the width from the deck to the top of the heads. That distance is a good two or three inches wider. Interestingly enough.... where the stock manifolds dump on a GM Square, are exactly the same on the diesel, sbc, and bbc (which makes sense given GM's philosophy of change only when necessary). Said another way. Bore centers on a SBC is 4.500 inches, 4.840 on a BBC.... which means the BBC doesn't have to be much longer - 4*.375=12/8 or 1 1/2 longer. The other bit on SBC is they are longer then necessary - when they first came out they had short water pumps, after the late 60s, that went away and the longer style became standard. I'd guess that GM made the longer pump to increase interchange between the Big and Small.