My goal is 390rwhp. This past weekend, I hit 371rwhp with the valves terribly out of adjustment. The valves were floating at high rpms, somewhere between 6k and 6400 (this was according to the guy that ran my car on the dyno).

Right now my plan is:

1. Adjust valves properly.
2. Go from stock throttle-body to 58mm
3. hack/port/polish MAF
4. make whatever changes with LT1 edit that need to be changed for #2, and #3.

I thought about removing my belt, but I can't do that on the street. Other than what I've posted above, what else could I try?

Right now the car has 306 cam, stock p&p heads with stock valves, elec wp, cold air, cutout, longtubes, 1.6 rockers/crane springs, stock bottom end.

I only need 19hp to reach my goal. So close, yet so far away.

 

port those heads

 

I recommend to leave the MAF alone.Maybe get better valve springs and adjust the rockers.Why is 390 your goal,I would be shooting for 400. ; )

 

what kind of injectors are you running? maybe some different injectors and a good dyno tune would help. between the throttle body, injectors, and valve float fixed, i think its an attainable goal. was that run with the cutout open?

 

At what RPM are you getting that peak RWHP? My guess is over 6k with that cam, in which case you MIGHT be experiencing some float unless you've you've got matching springs.JMHO.

If that's the case better work on the spring issue.
Doubt that going with a 58MM is necessary and certainly not messing with the MAF. JMHO.

 

They are ported. They still have stock untouched valves, though.

I wouldn't think I need new valvesprings. These only have a few thousand miles on them. They are the crane springs that most everyone uses with the 306 cam.

Well, my original goal was 400, but after seeing how far away I was, I decided to shoot for something more reasonable. I think that the heads could use a little more porting and polishing, along with bigger valves/valve job, to go 400 or beyond.

 

36# injectors, sorry forgot to list that.

I thought about a dynotune, but those are pretty pricey. Plus I'm not sure if anyone around my area...within say, 150 miles, can do one.

The 371 was made with cutout open.

Well I think it was around 6200, but I'll have to look at the dynograph. I left it at my g/f's house, and haven't had a chance to go back and get it. I always thought the 306 peaked higher than 6200rpms...more like 6500?

The springs are the correct springs for my cam. Wouldn't the rockers being loose cause some loss in HP, regardless of if the valves were floating? The guy running the dyno said he felt my car missing, or "breaking up" at higher rpms. I asked him if it was ignition related, and after looking at my graph, he said no. Then he mentioned it was likely valves floating if the rockers are loose.