2.19/1.88 valves in 3931063 heads

[Roger G.]

I've got an extra set of 3931063 heads for a 427/400 that I'm going to get rebuilt..besides porting,would there be a significant performance gain with 2.19/1.88 valves? Would the stock cam work ok with them? Thx

[Joe R.]

Re: 2.19/1.88 valves in 3931063 heads

Hi Roger,

What size are the valves right now? I would think the stock cam would work fine. What is your overarching goal? I plan to squeeze as many HP as I can from a stock appearing L72 (427 / 425). I am seriously contemplating a similar upgrade. Are you also planning to have your heads ported? Any other mods you plan on doing?

Joe

[Duke W.]

Re: 2.19/1.88 valves in 3931063 heads

I would expect if those heads are from a 427/400 they would have the the 2.06/1.72" valve set, and being as how the port cores are completely different than SHP heads I not sure if you could increase the valves to SHP size without hitting water. In any event there's not that much more to gain.

Head massaging works wonders on any OE engine regardless of the original configuration. Expect about 10 percent more top end power and the useable power range will extend another 500-1000 revs while maintaining OE idle behavior and stump pulling low end torque.

The OE cam is an excellent design for a torquey road engine that still makes very good top end power and revs. I don't recommend any changes to this engine other than head massaging (and stroking to 4.00" is optional), but keep the CR no more than 10.00:1, which should be attainable with OE replacement parts and a suitable head gasket thickness. On a stroker retarding the cam four degrees will increase top end power at a slight loss of low end torque, which will still be very ample.

You should also install valve springs that are equivalent to the second OE design that went into production circa 1969.

Duke

[Doug M.]

Re: 2.19/1.88 valves in 3931063 heads

I would expect if those heads are from a 427/400 they would have the the 2.06/1.72" valve set, and being as how the port cores are completely different than SHP heads I not sure if you could increase the valves to SHP size without hitting water. In any event there's not that much more to gain.Head massaging works wonders on any OE engine regardless of the original configuration. Expect about 10 percent more top end power and the useable power range will extend another 500-1000 revs while maintaining OE idle behavior and stump pulling low end torque.The OE cam is an excellent design for a torquey road engine that still makes very good top end power and revs. I don't recommend any changes to this engine other than head massaging (and stroking to 4.00" is optional), but keep the CR no more than 10.00:1, which should be attainable with OE replacement parts and a suitable head gasket thickness. On a stroker retarding the cam four degrees will increase top end power at a slight loss of low end torque, which will still be very ample.You should also install valve springs that are equivalent to the second OE design that went into production circa 1969.Duke

Duke,Not to get off topic, but would you mind explaining " head massaging " in detail. Thanks,Doug

[Roger G.]

Re: 2.19/1.88 valves in 3931063 heads

Hi Roger,

What size are the valves right now? I would think the stock cam would work fine. What is your overarching goal? I plan to squeeze as many HP as I can from a stock appearing L72 (427 / 425). I am seriously contemplating a similar upgrade. Are you also planning to have your heads ported? Any other mods you plan on doing?

Joe

Hi Joe, not sure of the valve size now...they are off a 69 impala...I was going to have them ported and polished, and maybe do the valves, and keep my original heads stock. The goal is same as yours, squeeze a little more HP, tinker with it, have some fun

I would expect if those heads are from a 427/400 they would have the the 2.06/1.72" valve set, and being as how the port cores are completely different than SHP heads I not sure if you could increase the valves to SHP size without hitting water. In any event there's not that much more to gain.

Head massaging works wonders on any OE engine regardless of the original configuration. Expect about 10 percent more top end power and the useable power range will extend another 500-1000 revs while maintaining OE idle behavior and stump pulling low end torque.

The OE cam is an excellent design for a torquey road engine that still makes very good top end power and revs. I don't recommend any changes to this engine other than head massaging (and stroking to 4.00" is optional), but keep the CR no more than 10.00:1, which should be attainable with OE replacement parts and a suitable head gasket thickness. On a stroker retarding the cam four degrees will increase top end power at a slight loss of low end torque, which will still be very ample.

You should also install valve springs that are equivalent to the second OE design that went into production circa 1969.

Duke

Duke, they are off a 69 impala, I assumed the valve size was the same as the 427/400, ie valve size 2.06/1.72, but that may not be an accurate assumption

[Duke W.]

Re: 2.19/1.88 valves in 3931063 heads

Duke,Not to get off topic, but would you mind explaining " head massaging " in detail. Thanks,Doug

I don't have time right now to write a 500 word essay on the subject. but I did explain it pretty thoroughly in the Fall 2010 Corvette Restorer in an article titled "A Tale of Two Camshafts".

Duke

[Doug M.]

Re: 2.19/1.88 valves in 3931063 heads

OK, thanks Duke, found the articleDoug