Quote:
Originally Posted by steve25
In no particular order here’s my 2 cents worth.
The performer rpm intake buys you nothing but a average loss of torque due to
1) a 3.750” stroke motor.
2) only 9 to 1 compression,
3) stock heads, no less small intake valve heads!
You will be far better off with a iron intake, or a standard performer.
Your Cam is a little big for neck snapping throttle response with only 9 to 1 compression, especially if your keeping the smog era gearing in the rear of the car!
You might think about adding Rhoads lifters if you do not mind the solid type lifter noise when hot?
Your valve springs should swap over to the number 15 heads just fine, but may need to be shimmed back up since they are used since you to have at least 120 psi on the seat with a 1.96” valve.
This shim process will hopefully still leave you with enough coil bind clearance and will have to be determined.
You did not state the connecting rods your running, but if they are stock and went thru a bearing failure session then it’s likely time for new one, forged new ones which are not only stronger, but lighter and add to performance by letting the motor rpm faster!
You may need a new oil pump which should be the 60 psi one, and a HD pump drive shaft will be needed also,
Piston wise I do not like those pistons you want to run, not so much because they have been known to crack, but because they are very very old school with there 5/64” compression rings that they use!
Pistons with 1/16” rings will make for less friction and in turn free up Hp and lower oil temps,
I would really like to see this build get to 9.5 compression and while the heads are off you could have a valve job done to install 2.11” valves and then mill the heads ,025” .
The big valve install will also pick you up some much needed intake air flow as a side benefit.
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Steve thanks for the reply. I’m very aware of the short comings on the build. Working on a budget and with what I got, I’ve learned a lot along the way. As soon as u find something better about newer parts there’s always a downfall somewhere to them as well (referencing pistons). Based on my research I felt at the time that was the best route, didn’t feel forged was worth it in this relatively low hp and non racing application. I agree about the cam. And it was funny someone else just threw this cam in when the motor was stock. It was way too big for it then and will slightly be too big still after all this work has been done but I’m hoping the 2500 stall makes up for it on the low end. It’s was a great performer before I pulled it and ran like a banshee. So I’m anxious to see it put back together. As far as the rpm intake I respectfully disagree. Everyone told me I would not see any gain from installing that and wow what a difference. The throttle response and acceleration improvise dramatically. I gained 2 seconds on my 0-60 time. A lot of these things are very relative and going off paper charts makes it sound like it won’t perform well, but at the end of the day the particular inner workings of each engine determine that individuals engines power. Being a 557 block I’m not going crazy and chasing massive power bc this block simply won’t handle it. I would work the heads like u say but imo it’s not worth putting the money into bc at that point, if I’m dropping a 1000 on cast heads I would drop another grand and just buy the aluminum ones. And in all honesty, I’m seriously contemplating doing just that at some point. I believe these will be temporary.
I did purchase a new Melling 60psi oil pump. I am reusing the stock connecting rods, they are currently being resized and checked at the machine shop.
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