4.5 stroker

[hotrodfeguy]

Jay Brown, On the 4.5 " stroker I know you clearanced the rod bolts for the cam. My question would be how much needed to be taken off? .125? Do you remember? Did you machine then weigh for bob weight/bal? Just looking for insight and or recipie here. Taking a serious look at this here myself. Do you feel it was worth it? Or if you had to do over go shorter?

[jayb]

Here are some photos of the modified rods and rod bolts.  Both the shoulder of the rods and the bolts had to be ground on one side in order to clear the cam lobes:





Was it worth it?  I would say yes, up to a point.  The point came when I decided to shoot for more than 800 HP.  Because of the minimal clearance, I couldn't fit the cam I needed into the block without further grinding on the rods and rod bolts, and I didn't want to go any farther on that.  So, I swapped to a smaller stroke crank to gain cam clearance, so I could run a .780" lift lobe.  The previous cam had been about a .710" lift.

I am a firm believer in more cubic inches as a route to more horsepower.  The bigger the engine, the harder it will want to pull air through the ports and the more flow you will get.  That means more horsepower for a given cylinder head and cam combination.  Plus you will get more low end torque by virtue of the extra cubes, meaning that you can run a larger cam and keep the same low end performance as the smaller engine.

Grinding on the rods and the rod bolts was not a big deal; only took a few minutes.  You might not even need to do it if you are running a smaller cam than what I was running.  So I wouldn't let that stop you from going for the big cubes.

[hotrodfeguy]

My solid roller is 262/272 @.050 .700 lift, I am guessing it would be an issue as well. Thank you so much for the pics. And looks like the route I will go for my all out wedge engine No worries now that I see what I am getting into. Thanks for your wisdom Jay
1) Were those 6.700" BBC rods?
2) Did you go with a custom piston, did the pin end up in the oil ring groove and was that an issue?

[jayb]

Yes, those were 6.700" Crower billet rods, and yes, the piston pin did end up in the oil ring groove.  The issue with the pin in the oil ring groove never has caused a problem for me, but I'm OK with a little oil consumption on my engines, because I get some anyway with the low tension ring packages that I've been using for the last few years.  I really don't know how much oil consumption having the pin in the oil ring will cause by itself, but I don't imagine its too much, if any.

[hotrodfeguy]

I am going to go for it, 4.5 stroke it is  One last rod question, I know your busy this weekend on the dyno, I would have loved to help wrench. But I was wondering have you played with the 6.8" rod ratio at all ? I just thought it was a idea to keep the piston up in the bore better skirt wise and improve the rod ratio.
260 @.050 DURATION CAM .700 LIFT

[jayb]

I ran one engine with a 6.8" Crower rod, and it worked out fine.  I didn't see a big difference between it and the 6.7" rods I usually run, though...