How much HP am I leaving on the table?

[Neener]

Here is the engine:
2000 Stock Explorer gt40P with TFS spring kit
FMS short headers
Edelbrock Performer with 4160 Holley
Stock 1985 HO Cam
3.55 gears with a T5

My timing cover gasket blew out and I need to replace it...while doing that I have toyed with the idea of a cam upgrade (yes another one of those questions). Anyhow, how much do you think I would gain with a cam? The Vert drives great right now and idles smooth. Just curious if I am leaving more than 10hp on the table with the stock HO cam if I never go past 6k RPM?

[erratic50]

1.7:1 rocker arms add more than 10HP. So yes.

You could always add 1.7's and underdrive pulleys.

[Ourobos]

A few more horsepower, and in turn a little less street manners.

My current 86, about the 150th fox I've restored, is a stock 5.0 manual, with full exhaust, explorer intake, smog delete and mass air conversion. I had forgotten how fun it is to drive a semi-stock piece with a stock cam. AND I got 20 mpg today driving over the mountains... So depends on your 'goals'

[erratic50]

A few more horsepower, and in turn a little less street manners.

My current 86, about the 150th fox I've restored, is a stock 5.0 manual, with full exhaust, explorer intake, smog delete and mass air conversion. I had forgotten how fun it is to drive a semi-stock piece with a stock cam. AND I got 20 mpg today driving over the mountains... So depends on your 'goals'

Yep....... good reason the retain stock bump stick. If you go to 1.7 and stock cam you won't notice a difference in cam at idle and will pick up some of what you want across the rev range.

[Neener]

And I can do 1.7s under the factory valve covers?

[JacksAO]

And I can do 1.7s under the factory valve covers?

I tried them on my bone stock carbed 85 GT with the stock cast aluminum valve covers and had an interference problem with them hitting the baffles under the ports for the PVC on the drivers side and the crankcase breather on the passenger side. As an experiment I removed the baffles but, then I had a problem with oil injestion through the PVC system.
Reinstalled the baffles and replaced the 1.7 rockers with the stock 1.6 and no more oil being sucked into the PVC system.

[Ourobos]

You can 'modify' the baffles if they hit. It's doable, depending on which rockers. The crane 1.7s were factory on the 93-95 cobras and fit.

[Mustang-junky]

Could use a spacer for the valve covers.

Are you leaving power on the table? Probably. Is it worth the expense of a new cam? Thats up to you. A TFS stage 1 cam would be a good, inexpensive upgrade if you go the cam route.

Jess

[BaconB8]

You’ll not be leaving much on the table. Might be 10, and at an rpm you seldom see.

[erratic50]

Several magazine builds I've seen over the years throw on an aftermarket AL induction setup, AL heads, headers, and a FR numbers cam or TFS and end up with results they declared a win in 390-425HP range.

Some got a bit too aggressive on cam and were at or below stock numbers until 2700 RPM. A few other builds have used stock HO cam and 1.7's. The one that used the small chamber Edelbrock heads to arrive at 11:1 compression yielded impressive results. They couldn't manage to pull it down below 1600 and it was making 330lbs of torque there. That build showed 400 HP and 400lbs of torque at their peaks.

It was past peak by 6300 but made ok power to 6500. IMO a shim limited hydro lifter or more oil pressure was needed - the graph looked like it was going into lifter collapse. Odds are it would have went past 7000 with a lifter but I wouldn't try it without a spring upgrade.

I almost routinely rev my tired old E6 head 86 mill to 6100 and bounce it off the rev limiter at 6250 with relative frequency. A worn timing set is giving me cam retard and a SD friendly cam from the mid-late 80's is helping it a little, but I suspect an open breathing 302 with stock cam and E6 or E7 would do it as well.

Anyway..... in the magazine builds they saw good area under the curve considering they built the cheapest option.

The Edelbrock heads are also a high swirl head which helped on the low end torque retention. The increased compression was key to the power it made. Staying at 9:1 would have been a 40+ HP drop most likely. High swirl does dictate less timing advance but that's because more timing isn't needed to reach peak power.

Really good numbers for a stock shortblock roller 302! Many strokers pick the wrong parts or the wrong tune and don't get there.

personally it's about all I'd want to extract from a stock 8.2 deck roller block. Much further and a bad tune could yield detonation and ultimately a split block. I'd rather leave power on the table and not break than find more power and experience more breaking.

anyone who's ran rounds in raceing knows the fastest car rarely wins. It's the car that's fast enough to get by initially while being able to go rounds and/or the distance.

Valve cover spacers are required with older valve covers. Steel 1.7:1 roller tip rockers from Crane is what the Cobras used and those do fit 86+ valve covers. Best part is the yield 1.73:1 while many of the others check in at 1.67-1.68.

You don't really have to worry much about PV interference there. You are still a long ways away on duration and total lift is not approaching 0.510 (notched pistons and stock gaskets). Reportedly also OK on 86 shortblocks below 0.49 without notches although that depends upon gaskets I'm sure. But generally no worries. Swap it in, bar it over once to be sure, and go for it.

[Hemlock]

While 1.7:1 rockers are a great/easy way to pick up cam lift without changing cams but unfortunately over long periods of time will wear out your heads valves guides and push rods due to their long throw and possible side loading of your valve train. A lot of people don't even take that stuff into consideration when making this switch. Just saying.

Robert

[BaconB8]

The 1.7 rocker thing is a bit of a bandaid mod for street cars. Its for guys who don't/can't install a cam.

If you're installing a cam, stick with 1.6 rockers.

[erratic50]

For most practical purposes I agree - if swapping cams stay 1.6.

A 1.7 can be used on the exhaust side if the cam doesn't favor exhaust but most grinds that make power these days are split duration already.

Better to do it with a cam cam if it's already apart anyway.

Just know that more lift lift is more wear. That's just the way it goes.

[854vragtop]

Here is the engine:
2000 Stock Explorer gt40P with TFS spring kit
FMS short headers
Edelbrock Performer with 4160 Holley
Stock 1985 HO Cam
3.55 gears with a T5

Anyhow, how much do you think I would gain with a cam? The Vert drives great right now and idles smooth. Just curious if I am leaving more than 10hp on the table with the stock HO cam if I never go past 6k RPM?

I have nearly the same setup as you in my '85 GT convertible, but with a Comp Cams XE264HR-14. (see my sig for my combo)
http://www.compcams.com/Company/CC/c...csid=1053&sb=2

With .512"/.512" lift, it's almost a perfect match for the P heads with stock rockers. It idles great, pulls hard to redline, and I haven't lost any low end torque. Since I don't have the factory vacuum control valve installed in the Weiand intake for full vacuum advance when cold at idle, it has a nice lope until the engine warms up. It's probably one of the milder cams for this motor.

I ported my P heads exactly per this article: http://www.diyporting.com/gtpin.html and http://www.diyporting.com/gtpex.html. I've never had the car dyno'd, so I'm not sure what HP I have.

[erratic50]

How much power you are leaving on the table depends a lot on other factors like "tune". Fuel delivery, advance curve, etc.

Odds are you can make around 300 HP and north of 370lbs with the parts you have. With more cam properly selected this combo often goes 360+ and turns 11's in N/A trim. That's what I've seen personally anyway.