OK guys, last time at the track I ran a 12.01 at 112.84 mph. I need to do a little more tuning on the carb and could add some race fuel, but I beleive thats all shes got.

I am running a Comp XR282HR-12 cam in my 350. I currently have 1.5 Crane Gold RR's. The specs on the care are 230/236 .510/.520 lift. If I go to a set of 1.6 rr's it will bump the lift up to .544/.554. My AFR 190's have been worked and flowed. They dont pick up that much between .500 and .550 lift, but they do pick up a few numbers. The rpm range for the xr282hr with 1.5 is 2000-5800. The intake is a RPM Air Gap that has been P&P and flowed to match the heads.

I know I have enough piston to valve clearance because it is stock bore and pistons. The heads have been milled and are 60cc's. I will have to check but I think I have retainer to valve clearance also.

I want to put this car in the high 11's even in the heat at the track. I know I could swap to a cowl hood, which I plan on doing later, but will going to the 1.6 rr's make much difference?

Thanks.

 

itll make a significant increase at the track, but on the street you wont feel them

 

Im not worried about the street. I dont street race.

What kind of gains am I looking at at the track?

 

idk, if your not picking up flow from .500 to .550 i dont think it will help all that much, maybe 5-10hp.

I run .600 on my AFR's tho as they peak at .550-.600 even tho advertised numbers from .500 to .600 only increase 3 more cfm or so. The exhaust picks up 4-5 cfm and peaks at .550-.600, so its beneficial to run extra lift.

If your heads peak flow at .550 then 1.6's should be used but only if your getting some flow increase from .500 to .550 on both sides intake/exhaust

extra lift does however make the cam act like it has a degree or two of extra duration so that may help too. the valves are open a touch longer with the extra lift travel

Hard to say if they will help. At most tho i will say 10hp which isnt bad, every little bit helps so i'd go for it if you cant do anything else to help the ET's

 

Both the intake and exhaust does pick up a few numbers about at .550.
We didnt go all out on the heads when we worked them, but we did help them compared to out ot the box.

If I go to a 383, there are a few places we can get more flow. Also going to a 2.05 intake valve will help.

Right now I can pick up a set of used Crane Gold 1.6 rr's for about $75 for 16.
Not bad compared to new. With more duration and lift, it should raise my rpm range a bit. For the price, I guess I really cant go wrong.

I was just curious if it would pick my et up maybe a few hundereths or a tenth.

 

i think it will give you a few hundreths for sure if your picking up a tad bit more flow and keeping valves open alittle longer.

Hard to say tho, as sometimes flow benches dont show true choke points. SOme benches i've seen post numbers where the heads back up at .500 lift but guys run .600 and make more power

 

I would think you would get an easy 1/10 and 1 mph from the swap. I would be sure and check your p/v clearance, as well as were the pushrod comes through the head. The 1.6 rockers move the pushrod closer to the outside of the hole in the head.

I'm running the same cam with my afr's, a single plane efi setup, and a rev kit. HP peak around 6200-6300 and makes good power up to almost 6800rpms.

The cowl hood will be a bigger gain. I would also fab up a cold air pan when you put it on. That's worth a few extra hp too.

 

I am toying with the idea of both. The 1.6 rr's and a cowl hood. between the both, that should put me in the high 11's.

My local track runs both 1/4 and 1/8, but mostly 1/8. My best 1/8 time was 7.64 et. I know the roll bar cutoff in the 1/8 is 7.50 et. I do not plan on ever installing a roll bar. So I guess anything between 11.50 and 11.99 I will be happy.

I guess high 11's on a stock bore/rods and piston carbed L98 isnt too bad.