Looking at making some changes to my 351w roller.. Need advice

[jruppert]

Hey guys. I have a 94 GT with a 351w that I put in a few years back. Last fall right before having to put the car up for winter I blew a head gasket. I didnt mess with it. So now spring is coming around and I am looking to get it out and get it fixed. I thought that since I am tearing have the engine apart to fix the head gasket I figured it would be a good idea to do some upgrades.

Currently has a trickflow stage 1 cam with 1.7 roller rockers with 30lb injectors and a pro-m meter. What cam do you guys think I should go with? The current cam runs good at idle but runs flat at or around 4200 rpm. The engine doesnt see much past 5500 rpm. Do you guys think 30lb is sufficient? If I recall, when using my tweecer and doing some analyzing with the injector timing etc, it seemed like I was pushing the duty cycle. I never really knew if I was reading correctly. Anyway.. any suggestions would be appreciated. I would be looking at an off the shelf cam for the moment.

 

[revhead347]

30lb injectors are fine for that setup. The cam is way too small though. I'm not going to make a recommendation, because I'm not a cam expert.

Kurt

 

[jruppert]

Thanks for the input on the injectors. I guess I thought 30 was pushing it. I will leave those alone for now. I was looking at a comp cam last night. Part # XFI236HR-14 and NX282HR. My only concern is the fact that I am running 1.7's

 

[jruppert]

Ok, I think I have somewhat narrowed down what I need for a cam but still unsure somewhat. Like I said, I currently have a stage 1 TFS cam with 1.7's. I have found a couple that will work and one I definitely like but the 1.7's will set the lift to over .600.

The cam that I do like is designed for 1.7's. XE276HR The only part that I dont know if I will notice much is that with 1.7's the overall lift isnt too far from the TFS stage 1 cam. The duration isnt too far off either. The only big difference is the rpm range. Here are specs..

TFS stage 1 with 1.6 and adjustment for 1.7's

Summit Racing Part Number TFS-51402000

Cam Style Hydraulic roller tappet
Basic Operating RPM Range 2,000-5,500
Intake Duration at 050 inch Lift 221 225 (1.7)
Exhaust Duration at 050 inch Lift 225 229 (1.7)
Duration at 050 inch Lift 221 int./225 exh.
Advertised Intake Duration 283
Advertised Exhaust Duration 291
Advertised Duration 283 int./291 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.499 in. .530 (1.7)
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.510 in. .542 (1.7)
Valve Lift with Factory Rocker Arm Ratio 0.499 int./0.510 exh.
Lobe Separation (degrees) 112
Computer-Controlled Compatible Yes
Grind Number HR-224/339-2S-12



Brand COMP Cams
Manufacturer's Part Number 35-328-8
Part Type Camshafts
Product Line COMP Cams Xtreme Energy Camshafts
Summit Racing Part Number CCA-35-328-8
UPC 36584038177

Cam Style Hydraulic roller tappet
Basic Operating RPM Range 2,200-6,200
Intake Duration at 050 inch Lift 224
Exhaust Duration at 050 inch Lift 230
Duration at 050 inch Lift 224 int./230 exh.
Advertised Intake Duration 276
Advertised Exhaust Duration 282
Advertised Duration 276 int./282 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.544 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.544 in.
Valve Lift with Factory Rocker Arm Ratio 0.544 int./0.544 exh.
Lobe Separation (degrees) 112


It seems to me that this Comp cam wouldnt be much different than what I curretly have. The rpm range TFS 2000-5500 vs Comp Cam 2200-6200

My biggest beef with the TFS cam is that it seems to fall short around 4700 rpm. The rpm range given is for a 302 and so I would assume this would drop with a 351w

 

[revhead347]

I would just go ahead and call Comp Cams. If you want to buy an off the shelf camshaft, they will be able to give you much better advice then we can over the internet. If you want to spend an extra $100, Ed Curtis can make you a custom camshaft. Not sure what his wait time is right now.

Kurt

 

[jruppert]

I took my head off today to check clearance. I had a blown head gasket so I had to pull it anyway. I wasnt really happy with what I came up with on measurements. I got .125 on intake and .210 on exhaust. My problem is that the dished area on the piston is .125. My other problem is that the dish isnt even round. It is round on sides but flat on top and bottom. The edge of dish isnt far enough towards the side to clear the intake valve. You can see the edge where the valve did touch the piston. I ran the rocker downward until the valve touched the piston.

 

[greengoblin95]

do you have your cam advanced any? it shouldnt peter out that low. but i guess if your fuel is off it would throw the power down quite a bit.