vortec heads on older gm
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They'll fit if your motor is a Gen I motor with conventional cooling system and not an LT1 Gen II motor. I have no idea how much you would gain from this head swap though, because I know little or nothing about EFI systems.
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To keep the TBI EFI system, you will need to use a Vortec-specific TBI intake (shown below); earlier intakes have a different bolt patterns and will not bolt up to the Vortec heads and the ports don't match even if they did.
One other way around the TBI problem is to use a Vortec carburetor intake w/a TBI adapter (also shown below) to mount the TBI throttle body to the Vortec intake manifold.
Click on images for link to Summit:
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.. Your '95 prolly has rather poor flowing swirl port TBI heads, the swirl thing kinda blocks the ports, so the superior flowing Vortec heads should give a noticable boost in performance. Especially with headers and free flowing exhaust... may also be going from 76cc chambers to 64cc chambers for a good boost in compression ratio...
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They will bolt on but require a Vortec to TBI intake. This will not have EGR ported from an exhaust crossover as it is not cast into the Vortec head. EGR requires external plumbing as was done on the 1996 up Vortec truck engines.
The TBI EFI will be OK with the original cam and rockers for the RPM range of the original engine. Given the computer limits top RPM and road speed you can't really get into problems unless you change the cam, rockers or terminate the EGR. If you do any of those changes you will need a new chip see these people if you do >>> TBI CHIPS <<<. If you want to rev higher and or increase top speed you will also need a new chip.
Bogie
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In that case you're better off leaving it as original. Unless you increase the displacement anything you do to the heads or cam will reduce bottom end torque, push the torque peak an horsepower to higher numbers but also they will be at higher RPMs than what the current LO5 peaks at. This will drive you to stiffer final gearing to restore power at cruise back to where it was with the swirl port heads.
If you really need more bottom end the best way to attack the problem is with more displacement, and the best way to do that is with a 383 stroker kit. The other ways of getting there with the engine you have is with a stiffer rear axle ratio. This will give the engine more mechanical advantage in all gears and will cause it to operate closer to its torque and power peaks in normal use.
You have to keep in mind that new trucks since the mid 1980's are very much an exercise in systems integration design. The Swirl Port head is made to work with TBI and actually does very well with a carb. The Vortec was made to work with port injection and with that set up doesn't surender much if any bottom end torque. But when that head is mated to TBI or a carb a very noticable drop in bottom end torque is seen. The overall performance gain in this situation for the Vortec happens above 2500 RPM which is significant, but unless you rev the engine up you can't get that advantage with TBI or a carb and these heads.
Bogie
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.. The Vortec heads will help low end torque (1500-3500 RPMs) some if they offer a change from 76cc chambers to 64cc chambers... but I don't recall if the swirl port heads are 76cc or not... just remember the swirl ramps blocking the intake port flow...
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There are 2 Swirl Port heads on the 350 engines the casting ending in 191 is 76 ish ccs the one ending in 193 is 64 ccs.
I have yet to do or to see a dyno run where the Vortec head picked up torque on the bottom end without also changing pistons from dish to flat top.
Bogie
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No I talking head to head comparison on an otherwise idential engine or as much as it can be given the intake also needs to change in-so-far as bolt pattern is concerned so while it's the same intake model i.e. Edlebrock Performer RPM for example it still is not the same piece of equipment from one test head type to the other.
Bogie
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My brother put Vortec heads on a 400 SBC and he ran 13.0 sec at the drags with a huge camshaft. He went to a mild camshaft and ran about the same time. He said that was because these heads flow REALLY good. You should gain HP either way. He was a GM Mechanic for many years.
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In my 85 C10 , I swapped 601 58cc to vortec 906 heads. They were milled to 60cc. 305 with a perfomer intake on both pre/ and vortec. My comparison would be no loss in pulling power at low rpm. The low end was the same, the mid band was a big difference.
A 305 , Q jet, performer cam, 3.73, 3000 stall, 28" tire. The basic foundation for a driven muscle car/truck.
To be current it is now supercharged, but before it was as stated.
Can you tow a tractor. I have towed as much trailer wieght as my class 3 hitch allowed, hundreds of miles.
A 305 , Q jet, performer cam, 3.73, 3000 stall, 28" tire. The basic foundation for a driven muscle car/truck.
To be current it is now supercharged, but before it was as stated.
Can you tow a tractor. I have towed as much trailer wieght as my class 3 hitch allowed, hundreds of miles.
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It is a th350c 3000 stall built by dynamic converter and followed the manufactures cooler instructions. With the drivetrain it is locked up at 65mph. Backing up with a trailer there is no problem. Normal driving it isnt noticeable . It footbrakes to 2200rpm for a big launch. Temps are normal. Not really sure what tow condition you are worried about. Pulled a weight distribution hitch with 7500lbs trailer, and it was fine.
Most newer trucks have 2600+ stalls.
If you have some concern about stall converters contact dynamic converter. An automatic drivetrain that works together as a package is priceless. The trans can be pulled back in a afternoon , not a big project. Should install a shift kit while you are under there.
Most newer trucks have 2600+ stalls.
If you have some concern about stall converters contact dynamic converter. An automatic drivetrain that works together as a package is priceless. The trans can be pulled back in a afternoon , not a big project. Should install a shift kit while you are under there.
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