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Discussion in 'Fox 5.0 Mustang Tech' started by fiveohlover, May 24, 2012.
Heyyy, bout time you guys showed up.
yup stock pistons and everything. so greg with the stock pistons could i run the 185 with the 58cc chambers or will i run into piston to valve clearance issues with a decent sized cam?
It is all about duration when it comes to piston to valve clearance. Lift is NOT the issue. You could run .700 lift with a 185 head with stock pistons if the duration at .050 is 220* or less. (assuming a 114*LSA) The cylinder head combustion chamber volume has ZERO effect on PTV clearance, only on compression.
I agree with the first part but not the second. You mill a head to reduce chamber volume, which effectively brings the valves closer to the piston, at least to some extent.
Your right, but I was referring to what the head cc volume was out of the box as the OP has not bought the heads yet. I should have been more specific.
i dont get it about porting. porting you are removing metal and are making things smoother right? so wouldn't porting increase the combustion chamber size?
You have much yet to learn, young grasshopper. PORTing is modifying the port. The port and combustion chamber are not one and the same. They are separated by the valve.
yes i am a noobie, dont worry i am going to get some help installing my h/c/i on my car.
so there is no way i can get the 185 with the 58cc chambers? i want to get the most compression from my stock bottom end
Don't know for sure but couldn't you just mill them down to 58cc? but I think that hurts the overall airflow a little though...(not totally sure my internet wisdom is not the greatest).
That's why you get them from a one-stop-shop that can set you up with exactly what you need. TEA milled my 205s from 65 to 61 cc. Other places can do this too. Or, you can buy them and have a local machine shop mill them for you, but you'll probably end up having more money in that.
Depends on the head, the valve job, and how much you have to cut off the head to get the CC that you want. Milling my 205s did not have any negative affect on advertised flow numbers. Mine actually flowed a few CFM higher than advertised, at least on TEA's flow bench. I bet Rick or Gregg could offer more info on that.
well if it hurts performance should i get the 64cc. whats more inportant airflow or compression?
I prefer to have a small chamber and then as much dish as I need to give me proper compression, but it also depends on the chamber shape and design (closed or open, heart, etc) I aslo prefer a Reverse Dome piston over a dish piston, modulars fords is the only area this changes..lol
A flat top and small cc chamber cylinder head will yield the BEST results, IMO. You maintain proper quench and the the flame travels in the complete area across the piston so you maintain complete combustion.
I have heard this before and I find the logic behind it pretty interesting. I'd love to see a dyno test of identical motors, one with a dish piston and small chamber and the other with a large chamber and a flat top or even domed pistons, both resulting in the same CR.
Check out the flow numbers on the 58cc vs the 72cc AFR225 ....different chamber shapes
ok i think the tfs 185 with the 58cc chambers is probably the best head for me. getting a ed curtis custom street sweeper cam and probably either tfs track heat or holley systemax 2.
should work ok, right? any body with past experience with the 58cc heads
With the 58cc head on a stock piston using a decent sized cam, yes you will have PTV issues. Your best bet is to stock with at least a 61cc chamber. If you would like to keep the compression up a bit talk to Fox Lake or total Engine Airflow and have the 185cc heads milled to the 61cc chamber.