What size tap is needed to "Chase" the Head Bolt Holes in a 1997 3800 ? Thanks

7/16-14

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86 Fiero GT 4spd - (pending L67 swap: VS cam, GenV) Build Progress eta: 8/13
98 GTP - Some mods

7 /16 x 14

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87 GT
series 1 3800sc (7.597 @88.53 1.579 60ft)
(series II swap in progress)
85GT Northstar
86GT 3800 n/a

Obviously your going to use a thread chaser NOT a tap. A tap will cut new threads if you run off course even a little bit. A chaser won't.

yes, just cleaning the threads.

I took an old bolt and cut lengthwise groves in it. Seems to have worked well enough.

sounds good, "home tool". what did you do, 4-6 grooves ?

One nice cut with a die grinder will be just fine. And using a tap will not hurt anything at all. Larry

[This message has been edited by trotterlg (edited 07-11-2013).]

OK, I've already got a reg tap. thanks

use fingers only with that tap. slight wobble to keep it loose. you can cut the threads. destroyed a block using Taps to clean threads. then I learned how. but I own a full set of thread chasers now.

Yeah you definitely don't want to damage the threads here, most of the holes go right into coolant passage, if you damage the thread it will be harder for sealant to work and you might get hidden coolant leaks into your valve covers.

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86 Fiero GT 4spd - (pending L67 swap: VS cam, GenV) Build Progress eta: 8/13
98 GTP - Some mods

I've been doing chevy, Pontiac, ford & chrysler V8s for 30 years with a Tap., I think I can manage it. just needed to make sure of the size,( that the threads weren't metric). Thanks