gotcha. I'm all for measuring it at the engine, but how do I actually hook it up? I'm assuming stock won't work, since the computer seemed to control at least some of it.

So what kind of aftermarket switch to I need? Thanks...

 

Oh, I know, but my 400 REALLY doesn't like it up there, I have a tendancy to run lean some times, which with the 9-1 compression, makes it cranky at 210ish. I've had problems with detonation before. I'm running 89 Octane fuel, and havn't had any problems, it just doesn't respond as well at those temps IMO.

 

The computer didn't control the fan in most models. The fan switch simply grounded the control leg of the fan relay using a single wire switch (ground through engine block). Most aftermarket two-wire temp switches will install in the stock location or can be installed in the water neck or manifold with an adapter (if needed).

 

I have that problem, too. My car can sit at 190 and run fine but as soon as it hits 200 it just starts to sound terrible...

 

what compression ratio are you running, and with what fuel? Because if it's that bad, you might really have a problem...

 

I don't know and I run regular unleaded. I don't think its the gas, though I think its the heat. I can't really describe the sound...

 

does it sound like a pinging noise? or a mechanical slapping sound? that would be detonation going off before the spark does. it's EXTREMELY hard on pistons...

 

Ok guys, so here's a question, what's the fitting size for the head? alot of the summit sending units say "3/8-18 NPT" others say "1/8-20 NPT" and the second one says "inline style" sending unit???? Here are the links...

http://www.summitracing.com/parts/DER-16739/
http://www.summitracing.com/parts/DER-16721/

Thanks...

 

ok... doesn't seem like this would be a hard question for someone who knew the answer...

 

It sounds like metal, like theres no oil in it or something.

 

Old heads are 1/2 NPT, newer ones are 3/8 NPT

 

Like, a "clicking" matallic sound, or a "slapping/banging/pinging" metallic sound?

 

Ok, so my heads are GM "487x" casting heads, I think they were a performance casting, (maybe vett?), but I have NO IDEA how old they are... I know that all of the sensors that went in my thirdgen (87) heads also fit in these, so they are the same as 87 heads, except for the valve cover bolts of course...