COBRA DOHC 4V vs. LINCOLN DOHC 4V?

Reply #15 – August 11, 2008, 11:33:49 AM

Quote from: booksix;231528

Digging up this old thread as well! Just because I may be building a different 'bird and have really been digging the mod motors as of late.

doodaa, you mentioned anything but boost of spray. So, this thing won't hold up to, say, 500-600 rwhp thanks to the help of a pair of scrolls running 8 pounds or so?

Also, what are the cobra vs mark computer differences? I found a 93 mark viii nearby for $550.00. I know a 96+ would be better, but just out of curiosity, could I use the engine, computer and wiring to get the same kind of power a 96-98 cobra had (of course, I'd still like to be able to apply boost at some point also)?

All stock Mark engines have a cast crank, common "wisdom" says that 400 hp is about top end for it though I'm not sure I've ever read/heard of anyone breaking one. The Teksid block will hold up to 1000 hp according to most accounts, with a Cobra steel crank and appropriate rods and pistons you're golden up to there. If it was me I'd forge the short block and install the later valve springs with anything doing much more than 6 psi of boost at anything above street rpm levels but I'm a cautious, broke sort who doesn't like doing or spending for work twice.

There are differences amongst the Mark computers, though I'm no tuner so I can't explain detailed differences. The 93s are commonly thought to have the most "aggressive" tune so what you have there is a cheap way to get 300hp pretty quick with that engine, computer, wiring, some bolt ons and decent flowing exhaust.... toss the Mark manifolds and cats adn get Cobra manifolds or headers and hi flow cats. A Cobra computer will be tuned for a lighter car and an intake that has different characteristics than either of the Mark generations, i.e more flow at higher rpm. Not sure I've ever seen one for sale seperately but I don't really pay attention to that. There are several guys around the country that can tune the Mark computers so it probably doesn't matter.

If you want to be complete in your research head over to modulardepot.com and do some reading, the Mustang guys have done this stuff, GTs have the same cast crank as Marks. Also find a thread at tccoa.com titled "The Mark is supercharged".