Smog legal upgrades?

[millmaster65]

Hey Fellas, Great site.
I have a 1985 K10 Sub in california.
Engine is good about 165-170LBS. average compression tested.
I tow a good size boat over a mountain pass about 1400 feet elevation.
I am getting some oil on spark plugs #s 4,6,8 near EGR valve , i'll assume valve seals are bad.
I can change seals or upgrade heads, I need smog legal part suggestions please.
Power sucks big time.
What replacement parts will give the best horsepower upgrade? Cam first? Then see about heads?
or a top end kit from Summit? I can do most of it in my garage but know little about sniffer proof upgrades.
Oh yeah ,last sniffer tes was way clean so I have some wiggle room.
Thank you in advance!

[eventhorizon66]

Are you planning on going through the whole engine?  Or are you just looking for bolt ons?

If you don't want to go through whole engine, I'd just fix the seals, give it a good carb rebuild, tune-up, and throw a good exhaust on it.

As far as exhaust goes, switching to a honeycomb brick style cat (if you haven't already) will be a very nice upgrade over the factory pellet style.  At the same time you can throw on a performance muffler from Dynomax or Magnaflow.  At the 200-250hp range single 2.5" with a high flow muffler will be fine, but if the budget allows upgrade to a 3".  The only reason I say single exhaust is to contain costs.  If you don't mind spending a little more go with 2.25" or 2.5" dual exhaust (remember you'll need two cats).  If there is even more room in the budget go with some CARB approved headers.  Basically the CARB approved ones will have accomodations for the AIR system.

If you do want to go through the engine, there are tons of good low-end torque cams that are CARB certified (if that's important to you).  As far as heads go (and I really wouldn't bother upgrading the heads unless you are at least freshening the whole engine) you will need some with an exhaust crossover to retain stock EGR, like THESE (rumor has it they are rebadged Dart Iron Eagle S/S heads).  You can also adapt L31 vortec heads to work with EGR, but you'll need to pull exhaust from the passenger header since vortec heads don't have exhaust crossover.  If you are going as far as swapping heads and cam, you should also round off the package with a good manifold.  For the stock-type heads an Edelbrock #3701 is a safe bet.  For the Vortecs and EGR, THIS is your only choice to my knowledge.

[eventhorizon66]

Oops, I forgot to ask.  Is it a 350?  If it's a 305 then definitely stop at seal replacement, tune-up, and exhaust.  Any more would be waste of time, IMO.  If you really want performance, you're better off saving up for a 350 or 383.

[millmaster65]

Yes it is a 350, sorry about that. Good knowledge! exactly what I was looking for.
The rebadged heads look good to me because they are not far off stock looking from the outside.
any specific cam in mind? I suppose I could spend 2K plus budget for a nice package if needed.

[eventhorizon66]

If I were planning on those Summit heads, I would also plan on doing some bowl blending to get the most out of them.  Check this BUILD THREAD out for a little more detail.  If I were to pull some numbers out of my butt, those heads could be worth maybe 15-20hp (and 10-20 ft-lbs everywhere) on an otherwise stock motor and 25-30hp or so on a warmed-over engine over 882-style heads.  Vortec heads could easily be worth 25hp on an otherwise stock motor and 30-40 on a warmed over engine (the more "warmed over, the greater the increase).

As far as cams go, here are two 50-state legal cams: Comp 260H & Comp 268H

On the subject of emissions legal cams, technically no one but you will know what cam you have in it, so if you pick a cam in this size range (meaning duration mainly) regardless of its CARB-approval status, you should be fine.  Besides its effect on emissions, the cam needs to be matched to the engine, the vehicle, and your usage.  For example, if you have tall tires and/or high gears, low compression (8:1-8.5:1), favor low end torque, want a smoother idle, etc., I'd lean toward the smaller of the two above cams.

[eventhorizon66]

Since you're not really targeting a specific performance goal - you just want more power, I'd start out with the full exhaust, full tune-up (ignition rebuild/timing, carb rebuild/tune, find/fix vacuum leaks, etc.), and seal replacement as I suggested earlier.  If the engine is currently comsuming oil and out of tune, you just might find that a good tune-up is all it needs.  These trucks left the assembly line with additional power available from a good tune.  If you do all this and you're still not satisfied, then you can dig into the engine with the only loss being the cost of valve seals and the time you put into changing them.

Notice I mentioned tires/gearing in my last post.  What is your gearing, tire size, trans?  These will have a huge impact on acceleration.

[millmaster65]

Yeah, this is a fairly new Goodwrench motor less than 80K miles on it.
P.O. has replaced cat and muffler but no fancy muffler like a Flowmaster.
Duel exhaust would be cool though.
I just purchased a rebuilt " stage two" Rochester carb from Jet Performance, it is perfect and a great price at that, better than stock.
Air/Fuel ratio was set w/ vacuum gauge.
Plugs are new, coil new, will check cap but not too many miles since replacement.
Wires are suspect because I hear engine static through AM radio, AZ wires suck so I will upgrade to quality set. Initial timing is set and advancing but not sure of total timing.
Vacuum gauge looks good..no leaks indicated but I will propane torch test anyway.
My underhood emmisions sticker has deteriorated and vacuum hose routing is always a concern with this motor. The Chiltons manual says this truck was rated at 150-165 horse at the tranny output???
700r4 tranny, funny you mentioned tire size, I got ignorant and put on 32x12.50s on it.
Next time I will buy 30" tires. Gear ratio is stock, not sure but cannot be the best for boat pulling.

[eventhorizon66]

Yeah, this is a fairly new Goodwrench motor less than 80K miles on it.

Oh OK, so you and I are in the same boat.  My C10 has a Goodwrench and I think it's a dog too.  I plan on someday building a 383 on the side, since my truck is my daily driver.  But if I were to simply upgrade the top end I'd probably go with Vortec heads and something in the size range of the bigger cam above.  Of course I don't have to worry with sniffer tests in TX.  But even in your situation, I'd favor vortecs.  Yes EGR hook up will be a bit more involved, and it will likely cost more in the end because of this, but the end result will be better for two reasons.  1) Port flow and swirl of the vortecs is vastly superior to the heads on your engine now and, to a lesser degree, better than the summit heads.  2) Vortec heads have a 64cc combustion chamber as opposed to a 72cc on the Summit heads and 76cc on you current heads.  So with your current pistons, stock head gaskets, and no machining to the block your compression will increase by about one full point - very good for power and efficiency.  Something to consider though, depending on the load your engine is under, this may require more than 87 octane.  The trade off here is sometimes worth it, though, as mpg can also go up with higher compression.

[eventhorizon66]

700r4 tranny, funny you mentioned tire size, I got ignorant and put on 32x12.50s on it.
Next time I will buy 30" tires. Gear ratio is stock, not sure but cannot be the best for boat pulling.

This is definitely worth further investigation.  You should pop the diff cover off and figure out what gearing you've got.  2.73's or 3.08's would be a major bummer on a K10 Sub.  3.73's would be more like it (this is what I run on my C10 with 29" tires).

Sorry about my double posts.  There is some sort of glitch when you try to post an essay.