I was looking at Summit at the bbc swap headers and noticed they mention that a gen 5 bb will only fit into a 91 or 92 and was wondering if this is true or a mistake on their part. It doesn't mention a gen 6 at all. The oil pan I have on my 400 sb that is in there now says that it will only fit a max stroke of 3.48" but it is a stock replacement 400 milodon pan? so that proves to me that they aren't always correct but wanted to see for sure before I find a motor, I am hoping to use a gen 5 or 6 so that way it is already set up with a roller cam.

 

Mark IV, Gen V and Mark VI blocks all have the same exhaust ports. If you use a tall deck block, exhaust becomes a lot more difficult.

Which headers are you considering?

 

super comps. I am going to be trading a t56 torque arm and x member to them. I haven't heard many good stories about them but the guy I will be trading with said they fit fine for him so I guess I'll keep my fingers crossed until they are in. any recommendations on a good aluminum head that isn't .400" raised on the exhaust side?

 

the .400" raise is a good thing, i wouldnt pass that over a fitment issue..

 

I see another swap header choice. Dynomax offers a third gen BBC header.

http://store.summitracing.com/partde...5&autoview=sku

The Hooker Supercomp swap headers are

http://store.summitracing.com/partde...5&autoview=sku

Dynomax = $556
Hooker = $510

Although there may be a few aftermarket aluminum heads without raised ports, most will be because it's a good performance enhancement. About the only aluminum BBC head without raised exhaust ports are factory aluminum heads.

Raised ports will always cause fitment problems. The headers need to pass under the front frame rails, or what passes for frame rails. The Hookers have the collectors under the rocker panels. It's a tight fit and raising them up because of better heads makes fitment more difficult. Because of how the Hookers run the #2 primary tube on top of the frame rail, you can't drop the engine lower to make them fit better.

The swap headers are not a performance header. Both only have 1-7/8 primary tubes and 3" collectors. That's good for a mild street engine. A good BBC needs at least a 2" primary and 3-1/2" collector.

My engine has 2-1/4 primaries and a 4" collector. Fitment was very tight and I even had to dent a few tubes to get them in. I use Ed Quay headers. I got a good deal on them but a good race header starts at around $1000.

The best fitting headers are a set custom made for your application.

re-reading your original post. The Gen V BBC does not have a roller block. Only the Mark VI is a roller. It's a one piece rear main and has a steel crank and 4 bolt mains. It comes with peanut port heads and a crappy casing which makes putting better heads onto it difficult unless the proper head gaskets are used. The Gen V is the worst BBC GM made and was only around for 5 years before being replaced by the Mark VI.

You can easily put a roller cam into a Mark IV block. My Dart block is based off the older casting and I run a roller cam.

 

is putting a roller cam in a mark IV the same as putting a roller in a sbc stephen?

 

yeah it is I know that much. I was thinking of gen 6 out of a suburban and then bbc bowtie heads. I like gmpp stuff they usually keep up with most current trends. I was going to go with ed quay's headers when I went big block, but I have an extra Spohn t56 torque arm and X member and someone on here had the super comps and wants to trade. this is going to be a street only car because Norwalk is pretty strict on vert's and I am not installing a 14 point cage into my vert.

 

I don't know what's involved to install a roller cam into a SBC. Probably the same thing as installing on in a BBC.

My Dart block has tall lifter bores so I needed lifters with a taller body designed for a Gen VI block. There are 2 styles of roller lifter connectors. Horizontal and vertical bar. These bars keep the lifters aligned in the bores which keeps them from rotating. I use vertical bar lifters. Pushrods are the same length but proper pushrod geometry always needs to be checked. Because I use longer valves, I needed longer pushrods.

Remove flat tappet cam and lifters. Install roller cam and lifters. Install a cam button in the timing gear to prevent cam walk. That's it. If it's a billet cam, install a bronze cam gear.

 

bronze distributor gear you mean?

 

Sure.