i am dropping a vortec engine into my blazer and i wanted to know if the headers on my 1986 k5 350 engine bolt up to correctly to a 1999 5.7 vortec engine.
CK5
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headers question
- Thread starter ChickenRammit
- Start date
Can Anyone Help On This Topic
wildmouse216
1/2 ton status
I don't think they will. The intake I know won't fit. If you call summit they will get you the number for the manufacturers number for your headers and you can ask them.
beater_k20
Banned
i know they will. for the sake of argument, i bolted a stock 305 manifold from my '86, as well as a '79 350 manifold to one of my Vortec heads, and to an 882 head. they will work no problem.
Exhaust port is the same, bolts are the same.
I think the only difference could be manifold issues, that 6 or 7 bolt difference that existed on some motors. I don't believe the Vortecs are setup to take 7 bolt manifolds.
I think the only difference could be manifold issues, that 6 or 7 bolt difference that existed on some motors. I don't believe the Vortecs are setup to take 7 bolt manifolds.
Inu-Hanyou1776
1/2 ton status
dyeager535, you hit the nail on the head. Starting with the '96 Vortecs, they went to using four vertical bolts on either side to bolt on the intake:
The bolt holes are located ajacent to the coolant passages. All the normal heads put on Vortec 305s and 350s used in the trucks and vans were like this. GMPP however has released a Bow-Tie version of the Vortec head that has the bolt holes needed to bolt on non-Vortec style intakes:
Here, we have an engine with a pair of the GMPP Bow-Tie Vortec heads. Notice the normal intake bolt holes on the heads as well as the Vortec type holes.
The bolt holes are located ajacent to the coolant passages. All the normal heads put on Vortec 305s and 350s used in the trucks and vans were like this. GMPP however has released a Bow-Tie version of the Vortec head that has the bolt holes needed to bolt on non-Vortec style intakes:
Here, we have an engine with a pair of the GMPP Bow-Tie Vortec heads. Notice the normal intake bolt holes on the heads as well as the Vortec type holes.
beater_k20
Banned
congrats on pointing out the obvious, however dyeager never mentioned anything about the intake flange. we all know that they are a different bolt pattern. the 7 bolt exhaust flange he mentioned is common to passenger car engines of the late 70s through the late 80s. nice try though.Inu-Hanyou1776 said:dyeager535, you hit the nail on the head. Starting with the '96 Vortecs, they went to using four vertical bolts on either side to bolt on the intake:
The bolt holes are located ajacent to the coolant passages. All the normal heads put on Vortec 305s and 350s used in the trucks and vans were like this.
FWIW attempting to put a regular small block Chevy intake on either the Bowtie Vortec heads, or the Fast Burns will not work. while it will physically work, the ports on both heads are higher, and will not line up properly with a standard intake. if bolted on they would create a huge restriction in the intake tract, cancelling all potential gains in power, quite possibly leaving you with a less powerful engine than if it were equipped with stock heads.
dyeager535 said:
SO ARE YOU SAYING THAT THE HEADERS PROBABLY WON'T BOLT ON CORRECTLY?
CAN YOU SHOW ME A PHOTOGRAPH OF THE OPPOSITE SIDE OF THIS HEAD?
beater_k20
Banned
they will work, i have done it before. i'll go get some pics of it for you in a little bit.
beater_k20 said:
COOL
beater_k20
Banned
well, wouldnt you know it... the truck manifolds i have are warped too badly to install on the Vortec head. 
i did install a 6 bolt flanged header though. the 7 bolts, as mentioned before are mostly passenger car units.
i did install a 6 bolt flanged header though. the 7 bolts, as mentioned before are mostly passenger car units.
55Willy
3/4 ton status
the headers will fit. my roomy has a 69 sporting a vortec and it has the heddman headers that are spec'd for a basic small block 67-72 truck. same with his girlfriends 68 camaro both running 98 vortecs.
