midge54

just an update, i have my engine completely together, all i need is to get the rockers adjusted in and new exhaust manifolds since the 305 manifolds off the old engine wont bolt to the vortec heads

skinny z

That's odd. What doesn't fit?

midge54

the very back bolt on the passenger side does not line up, on the 305 block there are 2 holes, the 305 utilizes the rear bolt, however the 350 vortec heads use the first hold, which isnt drilled in the manifold and the rear bolt overhangs out the back of the head

skinny z

I had done the swap years ago (on a 70's vintage 350) but went straight to headers and didn't attempt to use the 305 manifolds that were in the car originally.
What's to prevent you from at least getting a short header set that will bolt up to your existing cat back arrangement (other than money I suppose)? The Vortecs are excellent heads, possibly the best GM OEM casting out there, but they can definitely benefit from a good exhaust system.

midge54

well my thoughts are to getting shorties anyways, but i noticed they wont bolt directly to the y pipe so i was weighing either cutting and welding the reducer in place to accept the 3 bolt flange or just replace the entire exhaust from headers to tailpipe

skinny z

My original short headers came with a y-pipe that bolted right in except for the difference between the y and the cat o.d dimension. Other than that, it was pretty straightforward.

midge54

so did you just weld the y-pipe to the cat, i was also thinking about that route, however what is the rough hp gain difference from a new header and y pipe vs an entire system

skinny z

That's a difficult question. There are so many possible arrangements.
I'll say that short headers don't offer quite the same performance as a short system. There are differences among short systems too, especially in the diameter of the y-pipe particullarly where it connects to the header flange and again where it meets the catalytic location. In this case, bigger certainly is better. You'll have to search a little to see who offers the best parts in a short headers/y-pipe arrangement.
LT headers are probably the better choice as far as potential goes (although Dyno Don and his group friom SoCal have excellent results with his shorties) but the problem with LTs is the need for a custom built y-pipe. That can run a few bucks for a well built part.

And yes, I welded a 2 1/4" to 3" adaptor between the cat and the y-pipe. My cat back exhaust was 3" so the catalytic fit directly using a clamp.

Danny515

Good to hear you're getting close midge. Looks like i'm back in the ring. Fired up mine a couple weeks ago and took it out the first decent day, and had to figure the first time I hit the juice I end up with a problem. Really small crack in the block right at one of the oil galley plugs so every time I hit the juice it sprayed oil out of the block like a garden hose. So pulled it out, grabbed a new block, cleaned it up, and now starting to get it together piece by pice. Definitely no budget to work with, so gonna see how this turns out. All internals were atill fine, so gonna transplant into the new block and see how it turns out. Hopefully yours turns out good and all together and street worthy soon too

midge54

Wow that sucks to here, fortunetly for you all the internals are good, I just need to find the time to drop the engine in now

midge54

Ok guys next thing, I'm planning to drop this engine in this weekend, however I just realized I have no sensors in the engine block, heads or the intake. My intake is empty minus the carb and the t-stat so what all do I need to get and what do I go by as far as ordering everything for it. The intake is a summit dual plane intake, vortec heads, and 010 350 block

skinny z

Typically, the sensor for your temperature gauge (either OEM or aftermarket) will go in the head between number 1 and 3 cylinder.
If you're running an electric fan(2), the sensor to trigger the relay is located in the other head between 6 and 8.
Alternately, some run the temp gauge sensor in the stat housing or the intake coolant passage if equipped with a threaded hub.

midge54

Ok I think I'm starting to make heads with this. Now my question is for the coolant fan switch the goes in the pass head. When I look up the part for a vortec truck nothing comes up, however when I look up say an 87 Camaro 350 one shows up, do my question is do will a 87 sensor fit in the vortec head and does the vortec heads even have the hole in the pass side head for the sensor. Also will this 350 need a knock sensor being that it is carbed

skinny z

There is only one cylinder head casting and as such no real left or right. Both heads will have the same size hole. 3/8" NPT.
You'll have to distinguish between the temp sensor for your gauge/light and the temp sensor for operating the fan relay.
Aftermarket gauges typically come with their own sensor.
The fan relay sensors have several different connector types. They can be OEM or aftermarket.
In my case I used a Hyperterch sender that came with an OEM style connector.
If you've gone carbed, then you'll have no need for the factory knock sensor.

Atilla the Fun

This is as far as I got before I fell out of my chair laughing. Thanks guys! Porting 193s is silly. They won't respond. I tried them, before and after, on a then-new SuperFlow 1020. Extrude-Honing can help these, but cheaper to just do virgin 416s.

skinny z

First off, good to see you back at it Atilla. I hope you're well.
Now my question: Why bother with 416's? I suppose from your point of view the cost to port them is just YOUR labour. (Can't say the same for myself). That said, I would think that you can get better results, a superior casting and spend less money by buying a set of iron EQ Lightnings, RHS Pro Action or similar Dart heads.
Keep in mind that this is from an average guys point who also has no interest in taking the time to port an old cylinder head.

Atilla the Fun

Hey buddy, I appreciate the kind words, thank you. Bolting on a pair of stock, 100,000-mile 416s isn't for everyone, I admit. But my local yards only want $80 for a pair, and that makes it the cheapest way to get more flow than 193s, without noticeable losses of lower-RPM torque. If your budget permits buying new, then any of the 180-cc heads are a worthy improvement. For anyone living close enough to me, getting 416s and having me port them is cheaper than converting to salvaged Vortecs, and the results are close enough. I don't enjoy porting 416s, but I've done enough of them...

skinny z

I had to decide what to do with my old but upgraded Vortecs this season.
I couldn't see spending money on them for new guides and a valve job despite the fact they're modified for screw in studs and guide plates as well as Comp 26918 springs.
After the machine shop would be done with them, I could purchase a NEW pair but still have stock port forms and have to get them upgraded.
I decided to step up and purchased possibly one of the last sets of bare RHS Pro Torker 170cc Vortecs. Upgraded them with 918 springs (the head kits come with Ferrea valves but inadequete 987 springs).
I figure it's much like having a nicely ported set of Vortec castings with an excellent valve job. All brand new.

midge54

just an update, got the engine in and running, however having carb issues, i think the old q-jet is wore out cause it wont idle and has no power unless your not pushing the throttle pedal

Danny515

Depending on how much time you want to spend you can rebuild that q jet. I know, everyone is gonna say screw it and just get a holley, but I'm a sucker for the q jets. I got a rebuild kit for mine, tore it down, replaced most of the working parts - needle/seat, float, vacuum diaphragm - dipped it for a while to clean it all out, and I love it. But ive always been a sucker for the way it sounds when those secondaries open. The rebuild is a bit complicated if youve never attempted to take apart or rebuild a carb before, but if you take pics and lay everything out in an open area its not horrible. If you end up rebuilding it, I can give you the name of the site where you can get the rebuild kits for about $50, and maybe another $50 for floats, needle/seat, etc

midge54

I got a non cc qjet and it runs great

vincentg

👀 Sir the 193 heads are not Vortec heads they are swirl port heads for mid low RPM fuel economy. Vortec heads have no center holes and chamber is heart shaped.

WildCard600

This thread is 7 years old and the person you are quoting hasn't even logged into the forum for over a year....