Hi,
a couple of quick questions on the new AFR heads.

Some time ago I read on here that the threads for the temp sender in the AFR heads were the wrong size for the sender used in a C3. Is this true?

Has anybody used a set of AFR heads with Dynomax ceramic coated headers and, if so, were they angled plug heads & was there any problem with clearance with the Headers?

TIA

 

i can't tell you for sure about dynomax headers, but the AFR angle plug heads and hooker super comps don't have any issue with spark plug clearance.

the threads for the temp sender should be the same, and if they aren't for yours, adapter fittings are cheap.

 

I just went through this.

I have no idea what headers are on my car since they were already on there. They are C3 SBC headers, long tubes. I went with straight plugs AFR Street Eliminators and had no problems.

The temp sensor and plug hole were a suprise when I was installing the heads. They are the newer, smaller style holes. If memory serves, they are 3/8" pipe thread. I picked up a variety pack of brass threaded plugs from the Help! section at an auto parts store to plug up the pass side.

For the temp sensor, I picked up a single wire sensor for an 86 camaro or something. Any of the single wire later generation I SBC sensors will work. I believe it was around 10 bucks. When you look at the sensor, it'll look just like your old one, but scaled down.

Chris

 

I have the AFR 195 angle plug heads, the hole for the temp sensor is too small for the stock sensor. I bought a cheap adapter from an auto parts store, worked fine. I later moved the temp sensor into my intake manifold (vic jr) works fine also.

Also I have the dynomax ceramic coated headers, no clearance issues. Went in easy.

 

Hi Paul
My angle plug AFR 210's needed to be drilled out larger to fit the stock 72 temp sensor. A couple of bucks at a local machine shop.
Don't know about Dynamax headers, but my Hooker sidepipe headers had to be dented to install the #4 plug.
Still have the Trumpet???
Eddie

 

I'm using the position on the intake for my temp sender. Seems like it would be be more of an average water temp tan on the head.

 

afr big block heads do not even have a sender hole, neather does my intake, so i dont know what to do.

 

For the sender, I beleive you want a WT356 which is original for 82 vette. It is the 'Temerature Sending With Guage'. First time around I got the idiot light sender which looks very similar.

I've got an electronic data system in my car so cannot verify this sender is spot on with a stock guage, but this is what many others are using.

It's about $10.

 

Maybe buy a thermostat housing with the hole in it?

 

Hi Paul,

I have the new 195 Eliminators on my engine and I would not recommend to use the Dynomax headers together with them because of the shape of the exhaust port.
The AFR ports are of a square shape and they fits perfectly to a Fel-pro 1404 gasket. You can see a pic of the port in this article:

http://www.hotrod.com/techarticles/e.../photo_02.html

On the Dynomax headers the exh-ports are much more narrow in the shape, and if you put a 1404 gasket on the header flange you will clearly see the difference. It would be no problem to bolt the headers on and run the car but the narrow shape will for sure interrupt the exhaust flow and steal away a certain amount of the engines output.

I ended up with a set of Hooker Super Comps with 1-3/4 pipes instead. After a slight amount of porting on the flanges they ended up fitting the heads almost perfectly. I had some problems with the Hookers at the collectors, but that is another story you can follow here:

http://forums.corvetteforum.com/show...ight=magnaflow

I would have preferred the Dynomax over the Hookers because of the better quality ceramic coating, the shape of the piping and the much better price but I had to pas them on because of the narrow exhaust port.

Best regards, DK.

 

I used the straight plug heads. Cleared my Hooker sidepipe headers just fine. Of course the raised port height caused me all kinds of greif.

 

barry grant six shooter intake, has its own custom water neck housing. cant be replaced with any other housing. but drilling it for one is a thought. but it wouldnt look too pretty. thanks for the idea anyway!

 

what about putting your temp sensor on your waterpump? you could pull the plug from the top and use that location.

 

I've been researching the temp unit issue for my 195s and if you want to keep same accuracy of existing stock gage just install in the intake. I havent found or seen a decent adaptor.

Another issue is if you plug the head location it might be wise to use aluminum plug instead of steel due to thermal expansion differences which might cause a leak with steel.

 

Excellent info, thanks people
As mine is an '81 there is a sensor in each head (one for the gauge & one for the electric rad fan). Additionally, there's a coolant temp sensor in the intake for the computer (wgbsigns: I had to drill & tap the intake for the sensor).
Is there enough clearance on AFR180/195 heads to drill out the sensor positions & cut a larger thread for the stock temp sensor? I can do it easily enough, but is there any chance of breaking through into a port, etc? Another possibility is that the '81 water neck has a pair of TVS's fitted in it. Neither is used on mine so I could possibly modify it to take the sensors. As it is, the sensors look like a minor problem compared to the Header issue

I guess that straight plugs are probably the best way to go as I don't want to have to dent any headers (spent ages making an exhaust system without nasty restrictions in it).

DK, can you remember how much of an overlap there was with the Dynomax headers? I'm wondering if there's enough "meat" there to match the ports, or if it's a complete no-go? Nice exhaust system by the way. Don't do what I did with my polished exhausts & drive it during a thunderstorm with an engine oil leak. What a mess

Frank, what sort of grief did the raised ports cause? I've got a custom exhaust system which was a real headache to make. There's room for a bit of "tweaking", but not a lot (which is why I'm worried about having to change the Dynomax headers - the cost is one thing, but possibly having to alter the pipes is about as appealing as pulling my own teeth!).

Assuming I can sort out exhaust issues, do I go for the 180s, or the 195s? The largest cam I can see me running will have a lift of 0.454" & the 180s seem to flow as well as the 195s at lifts up to that. As the ports are smaller then the intake velocity will be higher, giving me more of that low down torque I like. So 180s look to be the sensible choice. BUT if I catch the hp bug at a later date, at what point will I find that I should have bought the 195s? Or, put another way, if I want the 180's, would I notice much of a loss in low/mid power if I dropped some 195s on there?
Thanks for the help.


Eddie: Hi there, hope things are good? The trouble with me trying to dink one of the header tubes is, well, put a big hammer in my hand & all sorts of expensive problems can occur
Yes, I've still got the Trumpet. With both that & the Vette to keep clean I thought I'd build an oily old ratbike that I could just get on & not have to spend any time cleaning/polishing. So out of piles of old bits I'd horded away I built a T100. Yet another one of my plans that didn't quite work out....
Link to pic if you're interested:
http://i41.photobucket.com/albums/e2...ul/pic0008.jpg

 

Bit's & pieces???? Piles of old bits????? It's beautiful!!!!:
Nice work Paul

Eddie

 

Hi Paul,

Concerning the Dynomax headers I would say it is a no go together with the new AFR heads. According to my memories exhaust port in the header flange is some 3-4 mm to narrow on each of the sides compared with the size of the heads. Top and bottom are ok but you would have to grind away this 3-4 on each side and by doing so you would already grind through the header pipes after the first 1-2 mm!!!

Maybe you can make some intermediate flanges in alu, lets say ½” thick where you make the one side fit the head and the other fit the headers but I guess this will make it necessary to make other changes to your existing exhaust too.

But Paul, don’t you already have AFR heads on your engine? With the low-lift cam you want to use I would really doubt that you will gain that much more with the new Eliminators. Why don’t you have some of out desktop-dyno friends put your existing and the new engine data into the computer and make a comparison?

My guess is that you would be able to make the same or more with the existing heads and a higher lift, maybe solid, camshaft and a 1,6 rocker combination. By doing this you can keep you exhaust and most of the engine and get the same output improvement for a much lower price.

What do you say to this idea?

Best regards, DK.

 

Thanks Eddie

DK,
Thanks for the info. I was thinking about getting an adaptor flange made, but isn't that going to possibly upset the gas flow? Plus there'll be the problem of doubling the chances of a gasket failure at the header/head. I don't think moving the headers out slightly is going to be a problem as I made the exhaust system with slip fit joints that will allow a bit of minor tweaking for positioning.

The heads I'm running are the stock originals. I was going to get some AFRs about 3 years back but finances took an unexpected pounding (as ever!).

I'll probably be known as the crazy who chose his heads due to the headers he was using, but the AFR heads are only just in my price range due to the current £/$ exchange rate. Having to buy new headers will push it over what I can afford, so I'll have a look at my second choice of heads before making a decision (TFS 23*).

Good point on the cam. I thought I'd change the heads & get the CR up to around what the current cam likes & see what I think of it. If it's a bit tame I was figuring that dropping in a 268H would just be a weekends work in the future. If that's not enough then I'll look at a hyd roller cam, along with getting the block decked & refreshed (or replace it with a 4 bolt), flat top hyper pistons, etc, in the future. What I'm trying to do is choose some heads that will work well with the current setup, but won't restrict me in any future changes.

 

Hi Paul,

Try and have a look at this intermidiat flanges from Dynatech:
http://store.summitracing.com/partde...0&autoview=sku

If you make something ala this with the AFR flang on the on side and the Dynomax on the other I think it should be possible to make it work without loosing to much output, but it will for sure make things more complicated.

It is my feeling that many people just bolts the headers on without taking the port fit much into considerations. They feel the improved output from the new heads and/or headers and they can't feel what amount of performance they are loosing with the bad fitted flanges.

Finally I don't consider this to be a AFR problem. It is more a Dynomax problem from my point of view. On a lot of other performance heads, like Sportsman2, Brodix IK180-200 and Cantfield, the Fel-pro 1404 gasket is specified, so here the fitting problem must be similar.

Best regards, DK.

 

Hi DK,
Thanks for the link, looks interesting. I've just been looking at Brodix IK180's & they look like they'll do just what I want..... except you've just posted that the Dynomax headers won't match up to them

I fully understand what you're saying about getting the ports to match the headers & would prefer some heads that match the headers than better flowing heads that don't. Thinking about an adaptor that will alter the gas flow; wouldn't it be doing much the same thing to the flow as an anti reversion cone stuffed into a primary? Or are anti-reversion cones old tech now?

Thanks for flagging up the header fit problem. How are we supposed to work out what headers will fit what heads without a restriction in flow, or can be modified to fit?! Dynomax & Hooker competition headers list the port shape as oval & the super competition (twice the price ) list it as rectangular. IK180 & TFS heads list port type as "D", while Sportsman II list it as square. Is there a standard size oval, or do I need headers with rectangular ports for D-ports on heads?