using stock size head valves on a stroker engine

[advinnie]

Just a quick one here im planning on building either a 2054cc or a 2188cc motor now I do have some heads cut for 94mm but they are stock ones that have been opened up with stock 35.5mm inlets and 32mm exhaust valves can I use these heads on either of these engines if not way not and what would happen? I'm only planning on rev ing to 5000rpm max. I'm still learning here so any advice would be great cheers all

[FJCamper]

Hi Advinnie,

Stock valves in a 94mm cylinder stroker will limit your higher RPM breathing. I'd use an Engle 110 cam and high-lift rockers to get all you can get out of it.

As you plan it, you'll have a high-torque 5000 RPM max-power production engine. That's not bad for a street car.

FJC

[Marc]

Heck, stock valves are starting to limit performance more than I care to accept by ~1800cc. Personally I wouldn't use stock-valve heads on anything bigger than a 1915, and even then I'd be porting the intakes to give them a chance of making power to 5K. Stock, unported heads on a >2-liter? Ridiculous IMO - after investing all of the effort (and expense) to build a stroker, it'd be sacrilege to strangle it with stock heads. If you're just after all the bottom-end grunt you can get with "no" top end, perhaps for a baja with too-tall gears/tires or a heavy Bus, you might make a case for it...but only barely.

...I havent come this far to build a bad ass cup of coffee just to try and drink it out of the stir straw.

[advinnie]

Cheers for the replys all I will be definitely be getting a pair of 40x35 heads. I'm planning on using a cam that's designed for 1.1 rockers and gives a valve lift of 0.415 and has a duration of 284 degrees but will the valve lift be enough? If not the after cam I have runs with 1.4 rockers and gives a bigger lift of 0.477 but has a shorter duration of only 278 degrees witch would you go for?

[Marc]

After all we went through on the cam selection for your last build you should know that more information is needed....MUCH more. What vehicle, what sort of usage? What do you intend to use for carburetion?