1979 Formula Thunderbird


I

illtww

New member
Hi All.

I am trying to restore a neglected 1979 Formula Thunderbird. It has the orig 5.7l Quadra Jet Carb'ed motor in it. The Exhaust manifolds are cracked and there is water in the oil...

The alpha drive was recently replaced...

Questions:

1.I wan to go ls1 in it. (More HP and Better Fuel Economy)
2.Is my best be buying a wrecked LS1 car and swapping over the wiring and computer and all over to the boat? (don't think this is covered in Dennis Moore's book)
3. Are there performance Ext manifolds for this boat?
4. Is there anyone that has done a similar swap that can shed some light on this?

Thanks,
Travis
 
My uncle told me many years ago..."nephew, speed costs money so how fast do you want to go?"
I said that to say this. There are performance manifolds and anything else you want in marine performance, just get ready to come off the hip with $$$$$$$ A nice set of Hooker Super Comp headers would do well on a street sbc for under $500 but marine headers start at $4,500 :eek: :eek: see what I mean ;)

The carb can make all the power you want. Many performance Formulas here are carbed and do very well. Both my boats are carbed. If you just want injection then the ONLY fuel system that will work in a boat even if you have an LS1 or any other performance engine is a MARINE fuel injection control system. The car stuff will not work on the water!!!!!!!!!! That is why Mercry Racing, Mercruiser and some other marine builders designed their own stuff. A marine injection system starts at $2000 and goes up from there unless you pilfer another boat system. The problem with using car stuff on the water is that a boat is always under load from it's own displacement in the water so the control system is designed for this condition. Cars don't have near this much detonating engine load. If a car control is used in a boat the engine will not last long due to compression loss or worse from detonation.

You could make short work out of it buying a marine "power package" that has everything and all you do is connect the canon plug and turn the key but be prepaired to spend $15k and up.
Or just replace what is broke and continue on as the boat is designed, that will put you in the water faster ;D

If you make more than 400hp then you should strongly consider a bravo drive. The alpha is good for sbc power ranges but that is an 80's build standard. Oh and don't stick a street racing engine in the boat because the compression and cam profile won't work on the water either. The first time the engine is decelerated the exhaust will suck water into the engine and it will lock up at the very least. That is called reversion.
I said all this because you mentioned putting car stuff in a boat :eek: bad idea. Boat engines come from the auto foundries but they are marinized to live on the water.

Good luck and keep us posted
 
What aquaforce said! ;D ;D

The LS headers for marine are very expensive! The port config is close to big block stuff so you could make adapter plates and use big block stuff, still lots $$$$. With enough $$$ the LS engine would work and be very cool.

I was in the same situation as you with my 1978 233 a couple of years ago. I was even able to get a couple of LS6's cheap. I ended up buying a pair of new merc re-mans c/w Bravo drives for the same money as building my own 383's or LS6's.

By the time I bought everything from ignition, carbs, pulley's, and freshened the drives to take the extra power it was quite expensive. Also I was able to sell most of the old stuff, heads, blocks, drives etc.

I know some will tell you the Alpha will take 300++hp, and it's true......if you baby it. I have no intention of babying it!

My justification was that I was going to be doing a lot of open water lake (Huron) running, river(no wake zone) and water sports, so I needed something that was going to be bullet proof and able to idle all day or run wide open all day if required.

Hope this helps ;)

Good luck, have fun and keep us posted!
 
A car injection system won't work, because the water flowing through the exhaust will kill the O2 sensor, unless you want to run dry exhaust (painfully loud). As for performance exhaust, you can buy the one's Dennis Moore sells, they will flow better, and if you get aluminum, you'll drop about 30 pounds a side.
 
If you add your location to your profile I can potentially put you in touch with an individual that worked on my '81. He does nice work. It still had the original block and setup but the Rochester carb was ditched long ago for a Holley 650 with a 1.5 inch carb-to-manifold spacer. I understood that it was good for a few extra horses...

The Holley would always run a little rich ...but would always run. The first owner swapped out the Rochester because he said it would a bear to tune.

My mechanic always told me that if the Rochester was a bear to tune, it was because the person doing it didn't have a good enough grasp on how to do it correctly and that if I ever wanted to put it back on (I still had it) he would be able to make it work great and get rid of the rich condition. He also said that a person could tune on the Holley all day and never get it 100% right, but that it would still always run.

I never made the swap back to the Rochester because it always ran...& then I sold the boat.

I had also just swapped the manifolds and still have one if them that's in good condition (I think). It's yours if you want it. Just pay to ship.

Keep in mind however that, as mentioned above, it will take a LOT of $ to get that thing (with the 5.7) to go faster than 50MPH. The 233 is a great hull design and cuts through what you ask it to, but it's also heavy.

You might consider going the 7.4L route if you really are speed hungry & cash heavy. Others may have better info on how to go about that process and what that will mean for your drive system.

For now, I'd say get it running, at a lower cost, get the other interior & exterior stuff on it right and then enjoy it for a year. After that you'll have a better idea on what direction you want to go in, can ask more people about what will get you what you want, etc... After all, it is a classis design that ALWAYS look great. Later it can go fast too!

Keep us posted.
 
I was in the same situation as you with my 1978 233 a couple of years ago. I was even able to get a couple of LS6's cheap. I ended up buying a pair of new merc re-mans c/w Bravo drives for the same money as building my own 383's or LS6's.

Resurrected,
Where did you get the Merc remans, and what did you end up paying? I have a 1969 233 with a SINGLE 160hp and am trying to figure out what to repower with. Thanks!
 
Sorry for taking so long to reply, i haven't been on here in a while! I got the engines from Pro-Tec Marine in Alabama, I think they were around $11,000.00 plus $600 to ship to Canada each.
Pro Tec 251-981-8114
Hope this helps!
 
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