Marine Intake

[Dropped88]

The 8.1 makes some impressive power and has to be one of the easiest swaps Ive done. but I opted to go DBC.

 

[L31MaxExpress]

The 8.1 makes some impressive power and has to be one of the easiest swaps Ive done. but I opted to go DBC.

I will say I definitely recomeend upgrading to the newer timing cover and timing set as well as putting a new GM crank sensor prior to install. I have had to pull an 8.1L from a GMT800 to get the tally wacker of a crank sensor. They rust in place and are almost impossible to remove in chassis. Then the cam sensor for the early model is discontinued. The later one was a crossover with the LS stuff and V6s.

 

[wiscomick]

Its basically a factory stroked 454 with LS style cathederal intake ports and matching intake manifold and LS electronics. The block is dual drilled for the standard old 3 bolt mounting pattern as well as the LS 4 bolt. It can either have a low mounted ac compressor LS style or a high mounted Vortec 350 style. Small block lower radiator hose fits it and I cut the upper hose in half where it crossed the water neck. It was an easier swap than a LS IMO because almost everything needed was either already on the small block, on the 8.1L or available off the shelf for a GMT400 without resorting to expensive swap parts. I used the DBW on the 8.1L with an inexpensive GMT400 6.5/8.1 DBW pedal.

Edit the exhaust ports are also traditional big block but being a tall deck block it did require a couple of header tubes to get a small dent for clearence.

Sounds like a great alternative to the LS swap. I have the 4L80E already waiting, lol. My truck also has no AC, no power anything except steering. Whatever I decide should be somewhat straightforward all things considered.

 

[wiscomick]

The 8.1 makes some impressive power and has to be one of the easiest swaps Ive done. but I opted to go DBC.

This is gorgeous. Is there more info on this swap somewhere? I'd like to not hijack this thread any more than I have.

 

[Dropped88]

This is gorgeous. Is there more info on this swap somewhere? I'd like to not hijack this thread any more than I have.

Ive got to update this build but the engine swap part is at the end.

90's retro makeover/restore

Time for another build did not plan on another but traded around and got here haha. So quick run down had an 03 suburban 3/5 drop cateye swap and 5 speed swap that a traded for a friends 90 sierra we LS swapped but he needed something bigger. And at the time i had no intention of keeping the...

www.gmt400.com

 

[Dropped88]

I will say I definitely recomeend upgrading to the newer timing cover and timing set as well as putting a new GM crank sensor prior to install. I have had to pull an 8.1L from a GMT800 to get the tally wacker of a crank sensor. They rust in place and are almost impossible to remove in chassis. Then the cam sensor for the early model is discontinued. The later one was a crossover with the LS stuff and V6s.

I didn't upgrade mine but it's the 2nd design that's still available. As for crank sensor it was already new but I greased it up before I put it back for that reason.

Idk how hard the crank sensor is in a gmt800 but in the 400 it's real easy

 

[L31MaxExpress]

I didn't upgrade mine but it's the 2nd design that's still available. As for crank sensor it was already new but I greased it up before I put it back for that reason.

Idk how hard the crank sensor is in a gmt800 but in the 400 it's real easy

GMT800 has a firewall that partially overhangs it. Nothing is easier to change that crank sensor in than a Workhorse/RV or Van though. Its right there when you open the engine cover.

 

[L31MaxExpress]

I managed to get a little done this afternoon. The wind blew continuously, aggravating my allergies more than they already have been. I did get the valvetrain in place and adjusted. I started wrapping the harness above the engine with the aluminum heat tape. Weather forecast is for 5*F cooler but much only 4-5 mph of wind vs 16+ mph with gusts over 20 that today presented.

 

[L31MaxExpress]

Made a little more headway this afternoon. Insulated the harness looming with reflective heat tape. RH header is bolted into place, the manifold is sealed up and torqued into place, upper plenum is on and although I did not take a picture of it, the fuel rail is in place. The fuel connections are also in place. I managed to break the CTS and need to replace both it and the heater hose fitting. A while back I discovered GM used the same restrictor fitting on vans that had both 1 and 2 heater cores. I put a non restricted fitting in the previous manifold so that both heater cores would have ample flow. Also waiting on a 10an male cap I forgot I needed to block off the former IAC passageway (often used for external EG and R) when this manifold was on a boat. Last time around I had a rubber cap on it and it did not last well.

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[L31MaxExpress]

Stopped for a hot cup of coffee. Close to hearing it run. Few more small details to address.

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