TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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Well it is 280 Prop HP, which is roughly 10% under crank HP. That would make the engine put out around 310 FWHP. Volvo Penta literature even states that it is TBI.
Found some more literature regarding the 280 HP HO TBI Marine engine from GM.
280 HP @ 4,600
365 TQ @ 3,200
It should be noted that these all have the same camshaft in them. It is the GM Marine cam which is also known as the HT383/Ramjet cam. It is 191/196 @ .050, .431/.451" lift on a 109* LSA. Its a torquey cam design.
Apparantly in 1997 the TBI HO Marine engine had Aluminum heads (Vette 113s?). I know around 1998-1999 they switched to the Vortecs with the TBI setup on it and made 320 HP!!!!
I've said the same and proven it with dyno numbers.
Yep, me too. Carefully choosing your heads has far more bearing on the output of these motors than just dropping in a .500 lift cam. People often neglect their head choice.
"So I'm going to get a hot cam and some 4.11s, but I think I'll just keep stock heads and maybe port them at some point. How fast will I be?"
That cam is the 94-96 Bcar LT1 cam. In the Bcar it was rated at 260 fwhp running into quiet mufflers. With aftermarket mufflers (but still with the stock N10 duals+cats) they make an easy 275+ fwhp, so the marine #s don't surprise me because they use the equivalent to the iron LT1 heads -- the L31 Vortec.
That cam is the 94-96 Bcar LT1 cam. In the Bcar it was rated at 260 fwhp running into quiet mufflers. With aftermarket mufflers (but still with the stock N10 duals+cats) they make an easy 275+ fwhp, so the marine #s don't surprise me because they use the equivalent to the iron LT1 heads -- the L31 Vortec.
That was my thoughts at first BUT, have to disagree the LSA is much different 109 on that cam vs 117 on a b-car.
That was my thoughts at first BUT, have to disagree the LSA is much different 109 on that cam vs 117 on a b-car.
The Marine/Ramjet/HT383 cam is very different from the B-car/Vortec LT1 cam. It has more lift and a narrower LSA. The Vortec/B-car cam is actually on a 111* LSA, not a 117* LSA. The F/Y-car cams are on a 116 or 117* LSA depending on year and application..
Not all the Marine heads were Vortecs either.
The marine engines did not get vortecs until around 1999-2000. Prior to that they had the 217 casting(083) and 193 castings as well as the 113 castings.
Fcar and Ycar cams were similar, both approx 201/207 deg, 0.45/0.46" lift (i/e), but IIRC the lobe sep was slight different and they probably had different part numbers.
The Bcar LT1 cam was also used as the factory L31 Vortec cam, and IIRC was used in the L99 (4.3 liter, 265 cid baby LT1 used in the std Bcar engine, 1994-1996) as well as on the 5.0 liter Vortec (L30?).
The Ramjet cam, also IIRC, fits spec-wise between the Bcar and F/Y car LT1 cams in terms of: 196/207 deg dur, and something like 0.45" lift when using 1.5 rockers.
I know the LT1 family of cams have their specs listed in one or more of the Tech pages, as well as in the FAQ pages here on TGO. I don't think anyone ever updated those resources to include the Ramjet cam. HTH.
Fcar and Ycar cams were similar, both approx 201/207 deg, 0.45/0.46" lift (i/e), but IIRC the lobe sep was slight different and they probably had different part numbers.
The Bcar LT1 cam was also used as the factory L31 Vortec cam, and IIRC was used in the L99 (4.3 liter, 265 cid baby LT1 used in the std Bcar engine, 1994-1996) as well as on the 5.0 liter Vortec (L30?).
The Ramjet cam, also IIRC, fits spec-wise between the Bcar and F/Y car LT1 cams in terms of: 196/207 deg dur, and something like 0.45" lift when using 1.5 rockers.
I know the LT1 family of cams have their specs listed in one or more of the Tech pages, as well as in the FAQ pages here on TGO. I don't think anyone ever updated those resources to include the Ramjet cam. HTH.
The RamJet cam is 196/206 @ .050, .431/.451" lift, 109* LSA.
Can anyone provide more information this motor? In case someone were to try and replicate it or even try to find one being sold. I was searching through Wikipedia and I think the 350TBI is a L31 motor, but I am not sure. I can not find much more information anywhere else. And the Wikipedia site says that Mercury Marine still makes the motor. However, the highest output motor (that appeared to be TBI) I could find from them was 270hp, not the 280 one. I did check out the Volvo Penta site and found a similar PDF file to the one listed above. But that is all the information given there too. Can someone provide some more information on this motor? I would love to get this swapped into my car if I could replicate it fairly cheap, or even find one for cheap.
That brings me to another question. Would there be any problems swapping this motor into a car? Underneath it is still just a Chevy Small Block right? Nothing fancy correct?
