gary96gt

ok, i have my 96 gt, full bolt on car with a 100 shot. my clutch is about done so im thinking instead of just replacing my clutch, doing a new motor too. here are my concerns

the mark 8 swap will cost me roughly $1500 with putting a new clutch in at the same time if i dont do anything to the motor and i get a good deal on a used but low mileage engine.

performance wise how does that compare to buying a nice aftermarket set of heads for my existing gt and keeping it a sohc.

my block is solid but has almost 150k miles on it, no knocks or ticks and doesnt leak/burn much oil. maybe a 1/2 quart per 3000.

im really shooting for about 300 to the wheels on the street and being able to shoot 100-125 shot for the track.

suggestions are appreciated



Thanks Guys

JC316

I did my Mark VIII swap with clutch for $500. You just have to find the right deal on the Mark VIII engine. The Mark VIII swap will get you roughly 275HP to the wheels, all motor, no tune or bolt ons. The trick is that it makes all of it's power over 3K RPM and I do mean ALL of it. So, to make a Mark VIII swap worthwhile, you need to get some gears for it.

If you situation, especially if you have headers, CAI, intake, etc, I would get a nice set of heads for it. None of that stuff will crossover to a 4V engine, so if you have LT's, you will have to get 4V LT headers, CAI, etc.

Looking back on my setup, I am very glad that I went to a 4V and the gains were impressive for me.

gary96gt

see thats my issue, i cant fin a great deal on a mark 8 local, i have to order one and have it shipped in or pay $600-$800 local.

basically whats better performance. 2v with nice heads or a stock 4v mark motor


btw thanks for the quick reply

JC316

Stock 4V will make more power. Again though, performance numbers are different than track times. A guy that I helped with the Mark VIII swap put down 276/288, but only ran a 15.1 in the 1/4 mile, he had 2.73 gears. That put him way down on the powerband when he shifted.

MU71L4710N

the 4v motor. a 2v with some decent heads won't break 300rwhp without some aggressive cams to back the new heads up. the 4v may put down a few less hp than a head only 2v, but the 4v is also spinning to 6850rpm where the 2v is 5800, so maybe 5-10rwhp less but a longer, better power band.

gary96gt

well good news is i have 3.73's so that wont be an issue BUT im looking for the best value. with 2v heads and cams im looking at probably $2000 but the mark swap including my new clutch im looking at under $1000 and then i get to spray and mod the 4v. thats the way im leaning but need a little more push. are the 4v's more stable and not limited to the 450 hp limit my 2vshortblock is limited to.

the other value im looking at is i have all my 2v parts to sell. all the c&l stuff should bring $500 used as its close to $1000 new. that would cover half the project...

Gary

any other insights?

JC316

The Teksid block is good to 1000HP. The rods/pistons/ are the same type that are used in the 2V Windsor, so they are just slightly thicker than your Romeo rods. I still wouldn't push it over 450HP with those rods and pistons.

Here is mine. All stock, right down to the exhaust. 3.27 gears. I litterally just picked a 97 Mark VIII engine out of the junkyard and slapped it in my GT.

http://www.youtube.com/watch?v=V7J0tcDjlwY

gary96gt

is there anything else you would do while its out? im going to start looking for a deal on a motor. im thinking that since its so close to winter i may nurse my clutch for the next month or two and since i have a shop, just make it a winter project. would you tear the whole motor down, different heads/headwork, etc.

again your help is much appreciated

MU71L4710N

where are you guys getting this idea that 4valve motors are all capable of insane numbers? the BLOCK is capable of it, but the bottom end is not. you are the second or third person i've seen this week under the impression that a mark viii motor is capable of insane horsepower as is.... and if you were literally talking about blocks, your 2v block is strong enough to take any amount of HP you will be adding to it.

JC316

If you are going NA, the C heads are what you want. They produce more power and torque N/A. If you want to go with boost, the stock B heads on the Mark VIII are great. If you can find a Cobra intake cheap, then go with that, also you have to decide what to do about the IMRC's. either keep the motor and wire it to a window switch, or delete them.