AFR 185's and valve clearance.

those pistons are huge valve relief... you will be fine with that cam!! JUST be sure to check the 347 when you put that together... We use the Mahle pistons and they have pleanty of clearance also.. however some pistons have less than othere... always check!! Cool??
Just me.............................

Thumper

...notwithstanding Thumper's experience -- measure YOUR clearance. It's the only way you'll know if you have enough. Two combos with the same components can have significantly different clearance - so you must measure yours. Given Thumper's experience -- it sounds like you'll find out you have enough. But the price you pay if you 'guess' wrong is high. And Thumper's probably not gonna leave FL and run up to MN in January with the parts, $ and labor to fix yours if you don't have enough clearance.

You probably won't have a problem with piston to valve clearance, but you should check it, it is easy to do with some modeling clay. Just assemble the heads on the motor with snugged bolts (if the mating surfaces are clean, you don't even need gaskets) if there is enough depth to the clay after rolling the motor over, then you are fine (especially if you didn't use head gaskets to start with, if it isn't okay, be sure to consider the thickness of your gaskets in the equation and possibly recheck with gaskets in place for certainty).

As far as valve notching goes, you can purchase kits to do it yourself that use the valve guide in the head as a guide and as long as you are patient and careful, you will have it done fairly cheaply and reasonably...however, I would put some grease around the gap between the piston and the ring landing to ensure you don't get shavings down in the motor.

Hope that helps.

Ryan

blacksunshine89 said:

I plan to measure, but I am just gauging my odds of it working out in my favor since I think the 185's will give me the best headroom for my present and future plans and I have already sunk enough money into my 306 and I am hoping to not put anymore into it. It only has to last one more summer and then I am building a 347. If I do have to notch my pistons, does anyone know what a general going rate for that done with the pistons in the block?

Click to expand...

just take an old lifter and pull the spring out of it.then put some small washers in the lifter and put the top back on and wolla soild lifter.just dont run the motor like that.you should be fine on the clearance.im running DSS pro lite pistons with a F303 and no problems

What Jozey said on the lifter....or you can use the drop valve method which requires removing one pair of springs but allows the heads to remain on the car -- no clay needed. You will need the same stuff you need to degree the cam - degree wheel and dial indicator. Be sure you degree the cam BEFORE measuring p to v -- cam/valve timing impacts p to v. Generally, advancing the cam will reduce intake clearance and increase exhaust clearance. Retarding it does the opposite. I prefer the drop valve method of measurement to clay. However, clay is the ONLY way to get radial clearances (edge of valve to edge of relief).

Also, on hrspwrjunkie's comments -- you don't need a head gasket if your piston is in the hole; if it's slightly out of the hole - you're gonna need a gasket. Not all engines are 'in the hole' at tdc. My stocker was slightly out of the hole - rotate the motor with no gasket and the piston would slightly lift the head..... I usually use the used on I pulled off with the head torqued to about 50 ft-lbs. on the old bolts. If you measure without one, just add the crushed thickness of your replacement gaskets to your clay thickness and you'll have your clearances.