I have a 87 roller motor in my Maverick with e7 heads that have had 2.02 valves added as well as some porting. The cam is an f303 the rocker arms are still stock (has beehive springs) I see a lot of people using 1.6 ratio rocker arms what is the stock ratio and what advantage would an upgrade do?
1.6 is the stock ratio, 1.7 would be an advantage by adding about .030 lift to the valve which mean more air/fuel going in. But watch you ptv clearance you may issues. Don't forget to check push rod length.
as MaverickDan mentioned.. it's always best to check clearance since even slight changes in the installed centerline(did you degree the cam?).. can cause issues on one motor versus another. I will say that the cam you mention does have a fairly low lift(comparitively speaking) and a pretty wide lobe seperation angle.. and I've run far more aggressive profiles with tighter LSA without issue on those motors. Not saying don't check PTV.. just saying it shouldn't be a big issue. That being said.. 30-35 thou isn't that much though.. and unless you have a zero deck height combined with a thin head gasket?.. I doubt that you'll see much more than a few horsepower out of the deal and clearance concerns shouldn't even come into play there. You will however add more area under the lift curve(you'll need good springs to handle the increased speed on/off the seat though).. and if tuned in properly.. can add even more power over the entire rpm range. as for the gains to be had from the factory stuff?.. they're hardly what anyone would call.. highly consistent in ratio.. across all rockers with some deviating as much as .5 ratio at times(might have been more than that.. but these days my memory ain't what it used to be). There was a factory ratio consistency test done quite some time a go(damned if I can find it now though) and it was surprising to say the least. IMO, if you want consistent power.. buy reputable aftermarket rockers to help get it.
I did not degree the cam a previous owner built the engine I think I can find that out though thanks for the info
I have an 88 roller motor with 1.72 roller rockers. Compare your cam specs to mine, and then compare your head clearance to the GT40s. I had PLENTY of room on mine. Actually thought of milling some off the heads to quench it a bit. My pistons are flat-tops with valve reliefs. But I did do a good bit of testing the clearances before I started that motor up the first time. The rest of my specs can be found here... http://scooper77515.fordmaverick.net/specsheet.htm
