Going to be replacing stock heads with worked over GT40's in the next month or so and looking to replace camshaft also. Looking at this one COMP Cams K35-320-8: Comp Cams 'Xtreme Energy' Hydraulic Roller Camshafts | JEGS

Is this a good choice? Will be using roller rockers, should I go with 1.6 or 1.7 ratio? My truck is just for street with little to no hauling. If there is a better choice please let me know about it. My truck is a 94 maf with long tube headers and 3" single exhaust. Also thinking about a converter if I pull the motor, what stall would be recommended?

Thanks, Rick

 

Also, would really like to use stock valve covers if possible. I see the Crane 1.7 pedestal kit is backordered until April, is there another comparable kit?

 

Little help?

 

Have you played with the CamQuest software? I'd really like to try a 35-510-8 on my 5.8L. It looks to build a little more torque than the 35-320-8 but a little less top end power. I've been told CamQuest is a little generous on actual peak hp & torque values, but it does a good job at placing the peaks in their actual RPM range.

I can't comment on how that cam you've selected will work aside from make sure your piston to valve clearance is OK & the springs you select will handle that valve lift.

Scorpion roller rockers seem to be well reviewed. I went with Crane 1.7:1 roller rockers for a very easy install & known stock valve cover clearance. But I had to buy them as Ford Performance (exactly the same part as Crane, different box) because the set marketed as Crane were backordered in September too. Of course, the Ford Performance cost more, what a joke. Here's a link, looks like they're in stock: https://www.summitracing.com/parts/f...view/make/ford

 

Thanks for the reply. After looking at the 35-510-8 I think it's a better choice. Now I wonder if it would be best to go with the stock 1.6 ratio instead of 1.7. Either way I'd like to use the Crane kit. Thanks for the link also.

 

Booth nice cams but the 320 will make more topend power which is what the 5.0 likes to do, I'd suggest 1.6 rockers with it just because there isn't any power to be gained beyond 0.500" lift with those heads so there is no point putting the valvetrain under more stress. Note this cam produces 0.512" lift with 1.6 rockers, Summit Racing info is wrong.
What gearing does the truck have? Anything less than 4.10 do that instead of a high stall.

 

Thank you Mr. Conaski I was hoping you would chime in. I do have a 4.10 gear, I was just kicking around the idea of a stall converter to get some thoughts on it, if there's not going to be much benefit to it I'll save that money for something else. I'll definitely go with the 1.6 rockers. So you think the 320 is the better choice?

A little more info. My original plan was to only replace the heads with gt40's and 1.7 rockers, port match intake, fix oil leaks and call it a day. Truck has 157,000 miles and has oil leaks that I believe are isolated to valve covers and oil pan, but may also be leaking at timing cover. So then I decided while I have it apart I'll replace timing chain and gears. Then if I'm going that far why not just pull the motor and rebuild with cam. The only thing that was stopping me was truck runs great and uses no oil. Also, truck has long tube headers with 3" single exhaust no cats, BBK 56 mm TB, 4.10 gear, silver fox valve body.

 

Well now that you mention that.. I was thinking a cam with those heads and the exhaust the motor already has may be a step too far for the stock PCM calibration. The whole package should make well north of 300hp which is outside what 19lb injectors can supply so you will likely be needing larger injectors and MAF and then tuning to make it all cooperate nicely.. especially if you have emissions tests to pass.

 

Forgot to mention I did have it dyno tuned and have a chip. In it's current state in makes 189 rwhp. I will get back on the dyno and have the tune modified afterwards. I'm in fla so no emission testing. New injectors and maf are no problem, what size do you recommend? And thanks again for the help.

Edit: Now that I've provided you with adequate info, do you still recommend the 320 over the 510?

 

Would 24lb injectors be enough? Still torn between the 320 and 510. Also, could you point me to a suitable maf?

 

what would you like out out of the truck? crispy, responsive part throttle pedal for daily driving? or just want more seat of the pants acceleration?

the 320 will give you more power with less pedal, and less power with more pedal than the 510...and vice versa.

there is benefit to lifts that are greater than the "flow ceiling" of the heads. the average lift being greater with 1.7's means the valve will stay open longer at the higher flow rates of the head. if cam lobes were square and pounded open instantly, having lift higher than the heads can support would be indeed pointless.

24# injectors is enough if you don't plan on doing anything else in the future.

 

Thank you guys. I'm trying my best to squeeze knowledge out of ya'll without wearing you out. I guess I'm looking to get all the low end torque I can to give more instant acceleration. I'm not looking for much after 5000 rpm. Does that sound more like the 510? Or even another grind besides the 320? This will be all I'll do to this truck, so if 24lb injectors will be enough that's what I'll do. Back to the maf, which size, brand should I be looking at, is there a particular part number? Thanks again for the help.

 

The red text was confusing as heck the first time I encountered someone else stating that. Seat to seat, duration is not changed, however, duration at 0.050" lift figures do increase. That's the most clear way I've conjured up to think about it.

 

I won't dispute the validity of that but... is there enough power gained to make it worthwhile? In most street applications my answer to that is no.

 

Sorry bud.. what you got now is about as good as it gets. Everything else you do to this motor moves the powerband up.. that is just the way it is.. this displacement simply will not make any significant torque below 2500rpm.