Jeep Strokers

OK this might be a question asked a thousand times.I want to use the crank 4 counter weights and connecting rods from the 258 out of my 82 cj.If I use the stock 4.0 pistons and rod and crank previously mentioned along with the stock 4.0 cam shaft .Would there be a big torque and horsepower diffrence from the stock 4.2 also using the stock cam what would low end tourqe be like as compared to the stock 4.2.Do I need to still use an adjustable map sensor and 24lb injectors and 63 mm throttle body or can I stay stock.The donor engine is from 1994 cherokee 7120 head & mopar injection.Not looking for a race jeep just something to go up hills with less efort and reliability.Thanks.Mike!!

If you use the 4.2 crank/rods, 677CP pistons, stock 4.0 cam, and port the '94 head, you'll have an exact copy of my "poor man's" stroker (see dyno numbers in sig.) . I used Ford Racing 24lb injectors, '01 XJ intake, modified Mustang 65mm TB (you could use 62mm Jeep TB), and have my homebrew MAP adjuster set at 5.2v. The engine makes at least 90% of maximum torque from 1500-4500rpm so there's plenty of low rev grunt to make it up steep hills.

I know all you folks know far more than I can compriehend,however why not use the stock 4.0 pistons?On a budjet.

I said 4.6 when I ment 4.5 stroker maybe in that case I could use the stock 4.0 piston.I thought the wrist pins were the same size on both 4.2 and 4.0 pistons

Wrist pins are the same size. Check to see what your final comp ratio will be if you use the stock 4.0 pistons. I think it will be pretty high.

mike0914nascar wrote:I know all you folks know far more than I can compriehend,however why not use the stock 4.0 pistons?On a budjet.

There are two issues with using the factory, stock bore pistons. The first is that they'll leave the CR at a high 9.7:1 and you'll need to run premium grade fuel to avoid pinging problems. The second is that the cylinders in your block will probably need to be rebored anyway to make then perfectly round and true, so you might as well get the necessary pistons that'll drop the CR down a bit.