wrong plug

[baxsom]

wierd,
the book says that i need a R44T for my 72 454.

when i took the first one out i right off the bat noticed that the socket that fits the R44T was too small for the plug. i ended up finding the right socket and noticed that the plug installed was a R44XLS. the one called for in the book wont even go into the hole far enough for the threads to start.
what is going on?

the R44XLS plugs that came out are all chocolate color with no evidence that the piston has came in contact with them but they are definitely not the plug that my haynes book calls for.

any suggestions?

 

[Z28ImpalaSS]

I would not use the Haynes manual as gospel truth. Do you have the original manual that came with the vette? Is this the original Motor? Maybe check in Tech Center here on CAC for info. Just a few suggestions that may help.

 

[baxsom]

it is a factory warranty replacement (CE engine)

i have been searching around and apparently the 396/427 engines used the R44XRlS as well. how do i know if it it the original 454 heads or if someone put 427 heads on it

 

[l81c3vette]

possible that someone stripped the heads trying to replace the plugs? they could have put a thread insert in and used a smaller plug with the same head range.

 

[baxsom]

i could believe that if it were only one plug but all 8?

looks like i need to pull the valve cover and get the number off of the head

 

[l81c3vette]

i could believe that if it were only one plug but all 8?

looks like i need to pull the valve cover and get the number off of the head

uniformity, so you wouldnt have to buy 7 of one plug, and only 1 of another.

 

[baxsom]

makes sense i guess but seems like a lot of work just for uniformity.
i mean i a grateful that i they are all the same but id be a lot happier if they do turn out to be 427 heads.

what is a good site that will tell me the head numbers for each engine.

 

[wallyknoch]

All early model BB 396/427`s use the 44 or 45 XLS 3/4 reach spark plugs requiring a gasket to seal the cylinder. The correct plug for a 1972 454, 'IF' the heads have not been changed is a tapered seat plug such as R44T or R44TS extended tip without the gasket.

It may not even be a 454. 396-454 all look a like and easily gives rise as to what size engine is really in the car. Time to do some serious casting checking.

 

[baxsom]

good idea
i have been looking for the casting # but just cant seem to find it

i must be looking in the wrong spots


ok found this
3999289 which according to this site
http://www.nastyz28.com/bbcmenu.html
is a 72-78 454 so the motor is the size that the VIN says it is supposed to be.

 

[JohnZ]

ok found this
3999289 which according to this site
http://www.nastyz28.com/bbcmenu.html
is a 72-78 454 so the motor is the size that the VIN says it is supposed to be.

That's the BLOCK casting number - just says it's a 454 block. You need the cylinder head casting number - pull a valve cover and you'll see it; that's what determines whether it needs flat/gasketed or tapered-seat "peanut" spark plugs.

 

[baxsom]

ok i finally got around to taking off the valve covers to look for numbers.

this is what i found
39048390
GM3T
1226

these were on each head.

i have done some research around and i found that these numbers correspond to a 67 427.

ok great i have heads off of a 427. is that a bad thing, good thing, indifferent.

would i be better off performance wise to go find a set of 72 454 heads?

 

[LVMYVT76]

Better sell the car since it has the wrong heads!!! WILL YOU TAKE $4000.00 FOR THE CAR TO GET RID OF IT????

 

[JohnZ]

this is what i found
39048390
GM3T
1226

Too many digits - is it 3904390?

 

[baxsom]

Too many digits - is it 3904390?

yeah sorry i fat fingered the keyboard
it is 3904390