vortec head conversion, few questions

[mtdave2]

my 1406 edelbrock performer carb had to have an adapter to work with my old stock intake, now naturally the adapter isn’t needed, the bolt holes do line up on the new vortec intake, can i just go get a new gasket and call it good? or do i need a plate for some reason.

Secondly, the water temp sending unit is a bit smaller. i just got one for a 97 chevy and it fits ok, shouldn’t have any troubles with the gauge as far as i figure, but perhaps one of you have ran into that before. also, any reason that i can just snip the wire and put on a normal wire connection is there?

i know these are some obvious questions, but im trying to head off troubles before i have them and it kills time when i have help working on the truck.


link to the build post
http://67-72chevytrucks.com/vboard/s...d.php?t=304830

[Irishpilot]

Get a new gasket and you are good to go. As far as the temp sensor, I just routed it up to the front of the manifold since it is the same size as the senor hole from the stock heads. As far as snipping the wire and using a connector, there shouldn't be any issues.

[mtdave2]

well the size is differant. the new one is 3/8. the old is 3/4? still shouldnt matter...

[WIDESIDE72]

I ran into the same issue a couple of weeks ago when putting a 97 vortec engine w/ Vortec to TBI Crusader intake manifold into a 1993 GMC. K20Go to a local hardware store or "Mom and Pop" auto parts that sells brass adapters and get a brass bushing to adapt the 3/8" to 3/4". Pick up some teflon tape to wrap the threads before you screw it in. (Be sure to wrap it in the direction that it screw in so that the teflon tape does not wad up when you screw it in.

[jkaylor68gmc]

awesome, I am doing the same swap this upcoming weekend!

I got the HVH aluminum double humps with the vortec style mounting.

can't wait, How does yours run?

[mtdave2]

i havent got it in the truck yet.. maybe this weekend it will be running.

i did find a 3/8 plug, and a sending unit from a 97 chevy. so i should be ok

[jkaylor68gmc]

cool, I though, oh yeah, it will be easy, dang, I have had to buy everything to make the swap, it is crazy

[cameeks]

Originally Posted by WIDESIDE72

......... get a brass bushing to adapt the 3/8" to 3/4".

It would be 3/8" to 1/2"

[70rs/ss]

Originally Posted by mtdave2

i havent got it in the truck yet.. maybe this weekend it will be running.

i did find a 3/8 plug, and a sending unit from a 97 chevy. so i should be ok

I read somewhere that the newer senders do not sinc up with the old guages, it fits the hole, but the reading will not be accurate. You can adapt the old style to the smaller vortec hole or open the hole up to accept the early style, or worst case senario, put the early style sender into the intake as opposed to the head.

[mtdave2]

hum that would suck.. i know others on this board have done this conversion, i wish they would help me out here!

another issue i have just found is my top a/c bracket. the end that connects to the intake bolt is angled, as is the stock intake....vortec is flat! so, looks like ill have to do some heating and bending ,,unless someone has done this and can give me another idea!

ugh, this was my fear when i was deciding to go with the vortec or not, i hate loosing my stock stuff.. might loose my long oil filler too....

[BP68]

How about a pic of that a/c bracket you mentioned?

If you a referring to the long oil filler tube in the valve cover, some trucks/suvs had a long plastic fill tube that screws in the valve cover and is topped with a screw on cap. I beleive my 98 had that setup.

[Bob 68327]

The sending unit for a late model will not work properly . I ended up with my stock sending unit in the thermostat housing . You can buy a t-stat housing at the parts store that the factory sending unit will screw in to. Otherwise you run an aftermarket gauge set up . I just went through this with my Dart heads . Hope this helps . Bob

[Jtrux]

You need to check the ohms of resistance. It's probably different.

[mtdave2]

see the box shape metal? on the stock intake, that is angled at a 45.

[mtdave2]

i have found several issues, everyone of them are related to the differance in the head angle.

the long oil flller tube (bend end and drilled new hole)

spark plug wire holdrers. (was able to bend them as well)

both the a/c brackes, one i hope to heat and bend, the other (pict below) ill have to build a custom bracket.




no hole for the rear bolt of the mount!!!


and the last one, one i have mentioned before, i took your advice, and got a 3/8 to 1/2 reducer and used my orginal temp sensor. i hope there are not cleance issues.

things are starting to come together...

[mtdave2]

oh ya, an no comments on the mess in the garage, its driving me crazy!!

[jkaylor68gmc]

Well I went to the dyno last night so I am going to begin my vortec swap also. You gave me a good idea, I guess I could cut my brackets and just reshape them to fit the flat mounted vortec manifold.

[ostncoln]

not to change the subject but, is that a aluminum intake painted orange? if so it looks good. i have been thinking about doing that but i cant decide how it would look.

[Ole Blue 68]

Originally Posted by mtdave2

oh ya, an no comments on the mess in the garage, its driving me crazy!!

That's a mess??

You should see my garage.

[Jtrux]

Originally Posted by ostncoln

not to change the subject but, is that a aluminum intake painted orange? if so it looks good. i have been thinking about doing that but i cant decide how it would look.

Yep.

[mtdave2]

ya, i wasnt sure i wanted to paint it, but im glad i did. i think it looks great!

[cameeks]

Originally Posted by mtdave2

......and the last one, one i have mentioned before, i took your advice, and got a 3/8 to 1/2 reducer and used my orginal temp sensor. i hope there are not cleance issues.....

Hold the header up to it and see if it clears. My Headman headers wouldnt.

[70rs/ss]

I wonder if that is going to clear, but also how acurate it'll be? The intake doesn't read too great, but may be better than the sensor where it is? Try and see, it can always be swapped later. The ac part should be pretty easy, just cut the bracket and weld it up to fit the front hole and runa piece of metal back to the rear holes and use that bolt. I wouldn't reconfigure the whole brack et with new, just cut and paste (weld!) Looks good and I am positive you'll be happy with the heads.

[Jtrux]

Originally Posted by 70rs/ss

I wonder if that is going to clear, but also how acurate it'll be? The intake doesn't read too great, but may be better than the sensor where it is? Try and see, it can always be swapped later. The ac part should be pretty easy, just cut the bracket and weld it up to fit the front hole and runa piece of metal back to the rear holes and use that bolt. I wouldn't reconfigure the whole brack et with new, just cut and paste (weld!) Looks good and I am positive you'll be happy with the heads.

I'm just bumping this for Dave when he gets around to posting pics of the mods he had to do to the brackets, heat..bend, heat..bend, etc. etc.

[ERASER5]

mtdave2, Look up the Low Buck build in the projects section. When the LS5.3 was put in, Kevin had the same issue. He found an adaptor that worked.

Other wise, if you have access to a lathe, there enough brass on your sender to cut it down to the proper thread.