89vette

I have AFR 195 heads on my 89 now. They have the same valve springs that came with the heads. I am looking to upgrade to a Comp Cams spring. The springs I have now are rated up to .550" lift and that is the lift I am currently running. What springs have other sout there with AFR heads switched to? Also what seat pressure is ideal for hydraulic lifters?

Thanks,
Jason

65Z01

The best bet is to follow Comp Cams recommendation on springs and seat pressure, the built they cam so they are the authority. Basically you want to be near the minimum seat pressure that will allow the valves to follow the cam profile just under valve float.

89vette

Yea good point. I guess I'll call them.

CFI-EFI

Are you experiencing some kind of problem? You don't mention any trouble in your post. If you are not getting into valve float or lifter pump up, what do you expect to gain? Money burning a hole in your pocket?

AquaMetallic94LT1

Jason is a bit smarter than that. So what are you up to ? Bigger cam maybe ? I have been getting itchy for a bigger cam myself. I'd really like to see 500 streetable hp from my setup.

89vette

Its not really trouble. The heads on my car are AFR 195's that I bought used. They were sold to me as barely used and they sure looked barely used. I was in a hurry to get the motor together and I should have taken the time to check all the springs while the heads were off. Now I should say that I am not having a problem with my valvetrain. My 396 with a Super ram makes 334 peak horsepower at the wheels at 4600 RPM! After that its kind of flat. When I had the Miniram on before, made less peak horsepower and it was at a higher RPM. On the miniram graph, the horsepower curve started to flatten out a little over 4500 RPM. I don't know if its related or not. I'm thinking that I may have a weak valvespring. The car has so much power that its hard not to break the back tires loose. Even in second gear. So I'm not really worried about it other than I know more power should be there. The ported Super Ram and AFR heads and exhaust system should make peak power at at least 5200 I'd think.

Jason

HiTech5

Jason - I have found that Comp is a little conservative on their valvespring recommendation. I as well as others have had good success with the Comp 987-16 springs. I have used them with the LPE 74219 cam that has .560 lift with a 1.6 rocker. If it's in your budget, I would recommend going to Titanium retainers as well.

89vette

I called Comp cams and the 987-16 spring is the one they recommended. Looks like a set of these and titanium retainers are in order. What is the installed height of factory AFR springs? I thought they were 1.900". Comp says that the 987-16 springs MUST be installed at 1.850". If I need shims do I have to remove the seals?

HiTech5

I had my AFR heads shipped to me with the seals installed but not the valves,springs etc. The AFR shims will slip right over the seals. One thing to keep in mind. the shim that the spring rests on must be a HARDENED shim. You can use regular shims under the hardened one without a problem. Another thing to get if you don't have one, is a spring height micrometer. Summit sells them pretty cheap or I'll let you borrow mine if you pay shipping both ways.

89vette

I talked to AFR and they said that the installed height of my valves is most likely 1.800". How do I get a 1.850" height if its set up for 1.800" now? I have to admit that I really have never set up a set of heads. I had other people do it for me.

Thanks,
Jason

ralph

if the springs are spec'd at 1.850 installed height and you only have 1.800, you can remove shims to increase the installed height (assuming there are shims in there now) or install them at 1.800..in which case the seat/open pressure will be higher than spec'd and you will have to check the pressures based on 1.800 starting point. May not be a problem, butr impossible to tell without all the details.