3.4 liter EFI Offshore

[powerabout]

I ran two T-4 versions (Fuel injected approximately 375-400 hp) of that engine in Offshore in 1981 on one of our factory Shadow Cats. At that time there were only 3 Offshore FULL RACE units in existence (mine and a spare). The following year the same motors were given to Mike Drewry and he ran all three on his 36' Maelstrom (actually Bill Sirois and Al Copeland did). This boat set an Open class record and later was powered by three OMC factory racing (not those consumer blobs) V-8's.The motors of course had aluminum flywheels and special "football" lower units (modified and cut down Mercruiser SSM's).

The engine you have looks like one of the "consumer" versions offered later. That "louvered" version with HD mounts yielded little more than the stock 300 hp "Harry Homeowner" versions that were a not very successful Mercury offering in the 80's. Later on Cosworth got involved with some of them and that upped the anty, but I doubt that any of the later versions exceeded the T-4's that we ran in performance or power.

T2x

That would be an interesting photo
GG at 2nd Effort ( Charlie Strang design) did a full shift twin pinion one , maybe that was later?

[Rhaines]

mxj. its a midnight.

[AirRide]

I ran two T-4 versions (Fuel injected approximately 375-400 hp) of that engine in Offshore in 1981 on one of our factory Shadow Cats. At that time there were only 3 Offshore FULL RACE units in existence (mine and a spare). The following year the same motors were given to Mike Drewry and he ran all three on his 36' Maelstrom (actually Bill Sirois and Al Copeland did). This boat set an Open class record and later was powered by three OMC factory racing (not those consumer blobs) V-8's.The motors of course had aluminum flywheels and special "football" lower units (modified and cut down Mercruiser SSM's).

The engine you have looks like one of the "consumer" versions offered later. That "louvered" version with HD mounts yielded little more than the stock 300 hp "Harry Homeowner" versions that were a not very successful Mercury offering in the 80's. Later on Cosworth got involved with some of them and that upped the anty, but I doubt that any of the later versions exceeded the T-4's that we ran in performance or power.

T2x

Whats speeds, with the twin "FULL RACE" 3.4 EFI Offshores, on the Shadow 30, did you see?

[T2x]

Whats speeds, with the twin "FULL RACE" 3.4 EFI Offshores, on the Shadow 30, did you see?

I'm sorry , I can't hear you....... there's some kind of a buzzing in my ear.

[BC Black Max]

I have the best girl friend. For Christmas she bought be an
EFI 3.4 Offshore - SP63 - 8341961

Its in all apart...but not for long!

[Greg G]

Speaking of 'ol bears .............

[Greg G]

And here is a blast from the past .........T4

[PARKER RABE]

there is alot of pics of those, in the rabco threads .

[FUJIMO]

5 1/2 year old thread coming forward...

[Dave S]

2 years ago I ran across a bunch of 3.4 stuff . I am still going to put one together....... Learned a bunch by having a bunch of them apart. The T4 has finger ports.......

[STEVERINO]

2 years ago I ran across a bunch of 3.4 stuff . I am still going to put one together....... Learned a bunch by having a bunch of them apart. The T4 has finger ports.......

I had a conversation a few weeks ago here in the UK with Fred Haunstein we spoke of old times when we first met when he worked and raced for OMC many years ago.When he changed camps and went to work for Mercury he said they were not big fans of finger porting but he introduced them into some of his race engines he said they even used them in a production engine but didn`t say which model. Eventually our conversation moved on to power output of the T4 engines he said the best they had was 460hp.

[powerabout]

460 3.4 ltr and they rev to 6000, thats a tall order, 360 would sound believable

[bernie]

I was on the 3.4 task force when the Cosworth came along, an engineer told me they had seen 450 -

[T2x]

With the injected T4s (actual T4 Tunnel boat motors), our all white "Shadow Cat" ran 96 or so race ready. The same hull ran about 72-75 with a pair of 2.4's (225-240 hp). the "Love It" Shadow Cat ran about 103-4 with 475 hp small blocks and about 100 race ready... so the T4's had to have something in the 400 HP area I would guess. Seems to me we spun them about 62-6400 but this was in 1981 so my memory cells may not be accurate.

[STEVERINO]

460 3.4 ltr and they rev to 6000, thats a tall order, 360 would sound believable

I would believe anything Fred said about outboard race engines this man should write a book he developed the OMC V6 2.0 looper engines that OMC won the 1975 World Championship in the UK with and developed the 3.0 litre OMC Loopers before moving to Mercury to develop all their race engines.If you want to see a Mercury T4 in action watch the 1980 Bristol Grand Prix Bill Seebold ran a 4.0 litre T4 and Tom Percival was much slower he ran a 3.4 litre T4 it's on you tube.