Question formula fastech 312 2001 6.2L
 

Hello everyone, I have just purchased a formula 312 2001 with 2x6.2mx engines, I want to change the engines for 2x454 mag I am wondering if someone has already done it? the holes for the exhaust arrive at the same position in the transom? do the engine mounts need to be changed? and my ration is 1.65 which pitch should I go 30? thank you for your answer and help

The boat doesn't have enough width to install BB, only 8' 3"

the boat left the factory with either 2x6.2 2x454 and 2x502 I do not understand that you say that

Yea, I think I've seen 312s for sale with 502s or 496s Seems like a big jump from a 350 or 377.

I just replaced the 350s in mine last winter, not much fun, but I'll follow along here for pics :)

Wrong. Very few 312's built with small blocks. My 98 312 came with 502 mags. 454 MAGS with 1.65 came with 30's (502's did also). Boat should run LOW 70's with 454 MAGS. If you're considering regular 454's don't bother with the switch. I have no idea about engine mounts/exhaust lining up, etc.

Sell it and buy my 2003 with 496HO in it!

no no I'm going to put 454 mags or 502 I was looking to find out if someone had already done the swap to know if the exhaust arrived at the same height etc

https://www.hardin-marine.com/Instru..._Locations.pdf

Unfortunately the locations are not the same, but it is pretty easy to move them. You will have to do a little glass work and gel.

yes I understand what you are saying but take a good look at the 2 pictures the exhaust belows on a quite distinct angle
https://cimg3.ibsrv.net/gimg/www.off...b8a107621a.jpg
https://cimg4.ibsrv.net/gimg/www.off...95bf3c8ecb.jpg

I didn’t realize you were going to run cast manifolds and risers. With that hose length you will be fine at sb locations. The motor mounts are probably a different story but I don’t know off hand. My factory big block boat left Formula with sbc exhaust spacing. It wasn’t an issue until I put on aftermarket exhaust that damn near touches the thru hulls.

I like the green pullies, I'd do red to match mine, but after chasing a belt squeal for years I'm gonna skip that mod. I do like the look though. I think a new alternator will fix it, but haven't gotten to test yet.

That bilge has to be tight with big blocks...I remember our 292 was tight with 6.2’s. Yikes.

drop a wrench...forget about it

the boat is a 312 and not a 292 they left the factory with the 6.2 454 and 502 power unit the boat has the same width as the 353 and 382 I do not believe that we make 2 boats make different stringers , the difference between a bbc and a sbc is the width

Because they left the factory with BBC means nothing...the fastech line is notoriously bad for have no space in the engine room.

look at an OL or cig...you can have a family party in the bilge and still have room for engines.

Why do you think my next one gets outboards... I'm too old for this ****...

hahaha!!!

I dreaded wrenching on the 292 and I was only 22 years old when I owned it. Had to be a contortionist to reach anything. spark plugs were particularly fun!!!

:lolhit:

Small blocks and big blocks use the same motor mounts in the same locations on the engine block. It is possible though that the engine spacing may be a bit wider on a BB boat. I am sure you could have some tails made if the exhaust doesn't line up correctly

There you go,285. Looks like you are clear to transplant. Post some pictures along the way and good luck. Welcome to the Formula flock.

2002 312 FASTech
 

My hull is set up for the factory bb exhaust locations , ie: wider . I have 6.2s it came that way. Engine mounts and crankshaft centers are exactly the same, GM had that all figured out. BB & SM Chevrolets will align the same in ANYTHING, car, truck or boat for that matter. Crankshaft center to mounting pads is identical on either engine. The big blocks are just taller in height. Your exhaust flex hose is located on an outward angle from centerline Thunderbird / Formula didn't care what engine package was going into the hull, they just cut all the holes universal because the Silent Thunder system wouldn't line up otherwise. Call Vintage Formula Tech Line: 260-724-1413. Scott Smith is the most knowledgeable Formula guy you can talk to. I have an over 30 year business relationship with him. He's running around somewhere, ask one of the Tech guys to ask him, Scott Ransbottom, Bryan Boehmer, Chris Everett, Lisa Clifton or Karen Reinhart. Better yet and easier Email them: [email protected], they will respond with the information or answer any questions you may have. Sarah Hillman or Tonya Hamilton director of communications will definitely respond. Have your HIN # for specifics. Walter Fletcher