🔧 Dorman 674-159: High-quality Driver Side Exhaust Manifold Kit for Chevrolet/GMC Models, in Sleek Black Review

Poor casting and/or machining. The casting hits the block before the ports can dock. I tried 3 of them, none worked, even with a thicker pad. The collector is sold under different names, but they all come from the same Chinese assembly line.

It fit perfectly flat on the head BUT had to grind down every hole where the casting was too thick in drilled and tapped Holes that weren't needed for this old motor home. Also, the front eyelet for the bolt was too small for the pressure required. It should be wider. Both collectors work properly. Up to here only a few kilometers.

Considering we have a vin# based truck, a 1989 GMC Dual R3500 I purchased these headers. The problem we are gradually discovering is that the truck has been rebuilt and the engine parts are from newer GM trucks. Maybe that's why they didn't fit perfectly. They still fit, so they work. Great price and fast delivery.

I bought this Dorman Manifold 674-159 for my '84 Chevy C30/454. The casting is of very poor quality and when I fitted the manifold it hit the engine block and did not fit snugly between the head and the manifold mounting flange. I had to sand down the casting numbers and then some more to make the mounting surface match. The collector still hits the block, but I'm afraid to keep grinding it. The 674-161 I bought for the right side fits great and was a lot better quality than I expected from…

I read some bad reviews about this product and thought maybe it was a percent of production. I was so wrong I have purchased many other Dorman products and have never had any issues with fit or functionality. One of the things the listing doesn't say is that the factory spark plug wire heat shields don't match or even come close. I know a lot of people take them off sometimes anyway. I've done it myself maybe a few times. Then I noticed that the caps on the connector wires were only a quarter…

See my review of the DORMAN 674-161 Exhaust Manifold. Direct replacement. Good quality. *** Updated January 31, 2020 *** Sorry; Like others, I had problems with a Dorman 674-159 "driver's side" exhaust manifold that fitted my 454 BB. The manifold is not directly above the head connections. There was a slight wobble when mounting on a head without a gasket. The OEM GM distributor had the part number and other information in raised letters/numbers on the outside of the distributor. Dorman (made…

I bought this Dorman header 674-159 for my '84 Chevy C30/454. The casting is of very poor quality and when I fitted the manifold it hit the engine block and didn't fit. between the head and the manifold mounting flange. I had to sand down the casting numbers and then some more to make the mounting surface match. The collector still hits the block, but I'm afraid to keep grinding it. The 674-161 I bought for the right side fits great and was a lot better quality than I expected from Dorman.

I've read some bad reviews about this product and thought maybe they accounted for 1% of production. I was so wrong I have purchased many other Dorman products and have never had any issues with fit or functionality. One of the things the listing doesn't say is that the factory spark plug wire heat shields don't match or even come close. I know a lot of people take them off sometimes anyway. I've done it myself maybe a few times. Then I noticed that the caps on the connector wires were only a…

See my review of the DORMAN 674-161 Exhaust Manifold. Direct replacement. Good quality. *** Updated January 31, 2020 *** Sorry; Like others, I had problems with a Dorman 674-159 "driver's side" exhaust manifold that fitted my 454 BB. The manifold is not directly above the head connections. There was a slight wobble when mounting on a head without a gasket. The OEM GM distributor had the part number and other information in raised letters/numbers on the outside of the distributor. Dorman (made…