Identifying 7.4 L

[Reel Poor]

Got this enging assembly as a Basket Case and would like to make sure the parts here are marine or would work. It is supposed to be used with a mercruiser I/O set up with an Alpha Drive in a 24ft Donzie sport boat.<br /><br />Casting # from bellhousig flange on rear of block<br />12550315.. "Found"..91 up Gen V 7.4L <br />Casting # from rear of block behind flywheel<br />MK........and H5... Same as above <br />Stamped # from right front of block deck<br />1G10M6J0... Same as above <br />Head casting # 14097088... "Found"..91 up Gen V <br />Cam # from rear end of cam<br />93029.......and 6209<br /><br />This engine has a one piece rear seal and a factory aluminum timing cover. It is a short block assembly and has 1/8in dome pistons.<br /><br />Any help with identifying any of these parts will be appreciated.

 

[lowshovel1]

Re: Identifying 7.4 L

http://www.mortec.com/castnum.htm should answer your questons at this web page.

 

[Reel Poor]

Re: Identifying 7.4 L

Thanks for the link Lowshovel1<br /><br />Found all the block and head info <br /><br />Still needing cam info<br /><br />Cam # from rear end of cam<br />93029.......and 6209

 

[rickf1985]

Re: Identifying 7.4 L

Can't help you with the cam numbers but the domed pistons would tell me that it is a high compression engine. It would depend on the heads as to how high but that is a lot of engine for an Alpha drive.

 

[Reel Poor]

Re: Identifying 7.4 L

Thanks taz <br /><br />The heads are gen V with combustion chamber volume of 118cc.<br /><br />I just need to find out if this cam (listed above) is marine compatable. Dont know the Mfg.<br /><br />I dont need problems with reversion.

 

[rickf1985]

Re: Identifying 7.4 L

You might try looking up Comp cams or Crane cams on the internet and give them a call. Even if it is not their cam they might be able to identify it for you. I like Comp cams, they have always provided me with good advice and products.

 

[Reel Poor]

Re: Identifying 7.4 L

You might try looking up Comp cams or Crane cams on the internet and give them a call.

Thats what im gonna have to do anyway. <br /><br />Pulled the cam today to check for any other identifing marks and noticed some damage to several cam lobes. Looked like the valves may have been stuck, or wrong length push rod. I noticed some slight galling on the lobes and also on the bottom of some of the lifters. Still have to check the rest of the valve train.<br /><br />Does anyone have any suggestions for a paticular cam that is tried and true. Roller or std hyd.<br /><br />Trying to maintaine about 400hp.

 

[rickf1985]

Re: Identifying 7.4 L

Roller is definitly the way to go but it is not cheap. I know Comp cams has a roller that they reccomend for the 7.4 but I don't remember the number. I am going to put it in mine this winter. I just did not have the funds this past year. Have you figured your compression ratio yet? If you want to stay away from a long overlap cam because of reversion then you have to watch out you don't get above around 9.5 or you will be running Cam-2 for fuel! I would still be afraid of putting that much power into an Alpa, but that is just my opinion.