sparky

Will 4.0 rods on a 258 crank clear in a 4.0 block

Outlaw Star

I have all the parts specs and will check for you later tonight.

SeriousOffroad

http://www.angelfire.com/my/fan/stroker.html
http://www.jeepstrokers.com/forum/
http://www.hotrod.com/techarticles/e...l_summary.html
http://www.jeep4.0performance.4mg.com/stroker.html
http://www.naxja.org/forum/showthrea...ght=crankshaft

Lead Foot

Not with a standard pin height piston. You will need to order Keith Black pistons part number IC944.

Hayden98XJ

Or the IC945 which will raise the compression. You'll also need to add spacers to the crank girdle for it to clear.

sparky

Thank you lead foot so the will clear with 4.0 rods and also what kind of valve to piston clearance will I have with this combo

Lead Foot

The valves on a 4.0 head are seated above the deck. So as long as you have at least .030 quench height, you will not hit the head and be fine. I recommend decking the block as needed to achieve .040 to .030 quench height and taking as little off the head as possible to achieve best efficiency. You want to keep the combustion chambers big as possible, so just skim the head until its flat.

By keeping the quench height low I was able to run a 10.5 static compression ratio and 9.0 dynamic compression ratio and still use regular grade fuel without predestination. Having the newer Obd2 system helps with that as well. I do run premium anyway though as I notice a smoother running engine and a little more power.

Lead Foot

This is really one of the most useful pages. http://www.jeep4.0performance.4mg.com/stroker.html

For detailed stroker questions you will get great response from jeepstrokers.com
My build specs are here. http://www.jeepstrokers.com/forum/vi...php?f=8&t=4293

Lead Foot

If he goes for less quench height, only having the 10cc dish the ic945 has will raise his compression too high in my opinion. He might get away with it depending on cam intake valve duration.

sparky

OK that brings me to my next question what is the most lift the stock valve springs can handle

Lead Foot

Depends on the year of engine. The springs can "handle" most common aftermaket cams. The problem you start to see is valve float if the springs aren't stiff enough. Too stiff and you get premature cam failure. I opted for Buick V6 valve springs from the junk yard. Working great. Didn't require machining either.

sparky

I have a 88 block and I'm gonna run my 96 ho head what can that cable spring support

Lead Foot

If you are upgrading the cam at all, I would upgrade springs.

sparky

What liter and year Buick springs should I get

Lead Foot

3.1 or 3.4 litre v6 with aluminum heads found 94-03 in like Pontiac Grand Prix. Part number vs-1642. If you cross reference that number you can find all the applications. You will also want to grab the locks and keepers.