[sharkbite]

looking for the correct postion for large hole. I'm getting ready to cut a hole in my hood for a tach I got from AMES. My problum is where to cut the hole. The temp. plate from AMES says the center of the hole should be 11 3/4" from the driver side edge and 11 7/8" from the back. This puts it right in the middle3 of the brace. An assembaly manual I have says 14 7/8" from driver side edge and nothing about from the back. This puts it in an open area. I can get as close as 14 3/8 from the driver side edge and about 12 1/16 from the back of the hood and clear everything. The assemaly manual also says it should be at a 2 degree angle from front to rear. So far I think 14 3/8" from side and 12 1/16 from back is the best bet but I'm not cutting till I know for sure. Anybody out there w/a factory hood tach on a 71-71 GTO that can tell me what they've got.. What do you think? Thanks.

[sharkbite]

looking for the correct postion for large hole. I'm getting ready to cut a hole in my hood for a tach I got from AMES. My problum is where to cut the hole. The temp. plate from AMES says the center of the hole should be 11 3/4" from the driver side edge and 11 7/8" from the back. This puts it right in the middle3 of the brace. An assembaly manual I have says 14 7/8" from driver side edge and nothing about from the back. This puts it in an open area. I can get as close as 14 3/8 from the driver side edge and about 12 1/16 from the back of the hood and clear everything. The assemaly manual also says it should be at a 2 degree angle from front to rear. So far I think 14 3/8" from side and 12 1/16 from back is the best bet but I'm not cutting till I know for sure. Anybody out there w/a factory hood tach on a 71-71 GTO that can tell me what they've got.. What do you think? Thanks.

[gtoformula]

I have an aftermarket (OE style) hood tach on my 1970. The installation was featured in a Car Craft (or other) magazine about ten years ago. I still have the article and could fax or mail it to you. The template that came with the tach would have caused me severe grief if I had followed those directions. You DO NOT want to cut through the hood brace. I might be able to take some measurements, but be cautious about cutting the hole. Taking more metal off is not too difficult ... putting it back is impossible.

[GTO71]

On mt 71 GTO i installed a hood tach, and I put it in the corrst location and it does require cutting some of the brace under the hood away. If I remember correctly the tach should si centered along the same line as the steering colom.

[BN]

Tracy, I have a 72 that I would like to put a hood tach on also, have you found anything definite out about where to make the hole?

[GTO71]

I looked in my factory assembly manual and it it does not list exact specs for the corrst munting of the hood tach,however it does indicate that a 3.75 inch hole be cut in the hood and half of the hole will gu through the inner panel (brace) on the bottom of the hood. Also the tach should be at a 2 degree offset to the passenger side of the car from the zero line of the hood this will be hard to duplicate beacuse the rear of the hood is not straight....go figure! Are you using a NOS hood tach or a aftermarket one cause the method of mounting them is differnt the NOS ones use rivets the oftermarket ones use none. Bottom line you do have to go throught park of the inner brace ....the factory did...if you want to make it look original I have a copy of the wiring diagram and the corrcet clips for the firewall. Good Luck

[BN]

GTO 71, How did you determine the correct location, did you use a hole saw to go through hood and brace?

[GTO71]

I saw the correct location on cars with factory hood tachs, then looked at the diagram on the GTO assembly manual and made the determination from the diagrams. I do not know of any GM diagrams on where the correct location is but I do not have a Fisher Body Manual. The paperwork from Ames sound like it puts it in the correct location if it is removing some of the inner brace of the hood......I was a mechanic a a chevy dealership at time I put on the hood tach and I took it down to the bidyshop to have them cut the hole in the hood and I could not bear to see how they did it, so I cant help you there but I sure aholee saw is what they used just make sure you have the correct blade or evrn take it to a body shop and pay a bodyman 20 bucks and a case of beer and have him make to cut with the correct tool.

[BN]

Makes sense to me. When you get a chance could you provide us with your measurments from the back of the hood and the side of the hood to the middle of the hole. Thanks,,

[GTO71]

E-mail your address and I will copy the diageams from the service maunal and the Body Manual. I wouls try and scan them but I have no scaner!

mabate9942@aol.com

To Tracy and BN

[GTO71]

BN, I sent out the diagrams today they sould get to you in a few days. TRACY e-mail me with your address and I will sent the diagrams to you also.

[BN]

Thank you, I'll watch for it.

[sharkbite]

So this was the 2nd hood i've put a hole in, the first was a Lemans hood and I used the temp plate from Ames in which the hole went throw the brace. No big deal till a friend bent my hood when shuting it. This time it's an Endro hood. I'm not takeing any chances. I cut the hole as close as posible to the brace with out hitting it and then put the tach on with a slight angle. I think it looks fine, of course I'm no judge at a show.