I would pull heads install new valves and springs new 10 retainers and locks,install mls head gaskets ,install500 or 525 cam ,if running pump 91-93 octane keep boost to 7max 30max timing to keep it safe shpuld be around 700 hp

i am not familiar with co performance but for them to say cam&heads won,t make much difference is wrong.i would shy away from any shop that does not know what cam&head upgrade can do for performance.

The 500efi and 525efi cams are quite a bit different, and in my opinion, the 741, or 525efi cam, will kick the 500efis azz in this application.

Stock HP500 specs
222/230 110 LSA
.576/598

500EFI specs
230/236 114 LSA
.598/610

525EFI specs
236/244 114LSA
610/632

Crane 168741 specs
236/244 112 LSA
.610/.632

The much larger 420 blower , is gonna be a good improvement in power above about 5,000 engine rpm. Below that, its not gonna make much more power than the 250 blower, maybe even less due to the small overdriven blower making good low end power. In order to really see the gains from the larger blower, I recommend spinning the engine in the 5500-5700 range to take advtange of the larger blower, and you need a cam that works well there.

The stock heads dont flow very well. Crappier flowing heads, will like more duration than an engine with afr , dart, etc.

Another often overlooked thing is the safety factor. Smaller cams can build more low rpm cylinder pressure, which can lead to detonation. I personally would dyno the engine, and give it the timing it likes, with a proper timing curve. I dont believe in one set magic timing number, to be "safe" . Ive seen alot of guys slap blowers on their engines, and run retarded timing thinking its "safe", and end up tuliping exhaust valves in a short time.

Fwiw, the 600sc mercury engine, 502 ci with 420 blower, ran 33 total timing. The 525sc engine, ran 35 deg total timing. The key is not bringing all the timing in too soon. Blower motors arent NA engines. Mercury didnt bring max timing until until nearly peak HP with their stock sc timing curves. I personally have written 3d timing maps, that have shown an increase in low end torque, with as much as 10 deg less timing in the peak torque area, and as much as 30hp more at peak HP area with a tad more timing there.

And of course, fuel tune must be good as well. Im not sure how a cam with 6 deg less intake duration, and 8 deg less exhaust duration, is comparable as far as saying "either one is fine" . There will be a substantial difference in the upper rpm power band , by changing 6 degrees of intake duration and an additional 8 deg exhaust duration with same LSA

My recommendation is from builds that i have been involved with, seen the results, and as well as a couple cam software programs that some engine builders use. The 500efi and 525efi cams, are quite a bit different, and on a deal like that, could be a substantial amount of power difference at wot.

Fwiw, same build you have, 525efi cam, chiller, 871, 7lbs , made 760hp at 5600 on a buddys build, and has ran great for years.

my plans are to pull heads and do a head job. also I was going to put clamedic gaskets. I really want more hp but I do want to be safe and reliable. It was cp performance I talked to and also teaque. . not a lot of help. I would like to gain some torque and mph . I have a xr drive with 1.5 gears . and I do have a super chiller and 750 holley carbs

Clamedic gaskets ? Where does one buy those ?

What kind of dressing do you put on those ? Can you get it over the counter or is it prescription only ?














Sorry. Weird mood today. Just sounds like an STD or something. Hah.

so if i understand correctly ,are you saying cp performance and teague marine told you a cam&head upgrade won,t do much for performance?

Yes sir

yet they both sell aftermarket heads&cams!makes sense to me.

i guess i,and many others must be wrong!