The Silver Buick's 1969 Firebird OHC six project.

[TheSilverBuick]

I got a handful of internet opinions that generally concur that 3" pretty much right after the turbo will unlikely effect my "600HP" goal. The turbo outlet is 3.5" and the only reason I have a 4" on it is because I got it for $20. Realistically cost will be the reason for which ever exhaust I go with. I think the cost for 3.5" tubing is a lot more than 3". I'll be re-looking at it soon though. Reducing from 3.5" to 3" near the rear axle shouldn't hurt anything for sure. I want to keep it single exhaust because it being an inline engine, and I plan on keeping all the fuel side on the driver's side of the car.

I need to find or buy new bolts for the balancer and get it to the machine shop so they can do the final balancing. Hopefully it's zero balanced or I can ask for it to be.

Got the 4L60e I'm going to have professionally built put into a GM transmission crate I'm borrowing from a local guy that is on one of the inline engine forums I'm on. Hopefully will be shipping it out this week.





In the mean time, after I get the Firebird up and running again, I need to install this older 4L60e that I put a mild shift kit in but is really in unknown condition otherwise. I can "practice" my transmission tuning and setup on this one to make sure I have everything setup right before the good transmission gets back.

[AndyB]

Sizing your exhaust will matter a little on how long the downpipe actually works out to being. You'd probably be surprised at how much power you can shove through a fairly small-bore pipe, if the temp has dropped and they've contracted down a bit. Unless you're going for every scrap of power, in which case you'd be just dumping it as close to the turbo's flange as you could swing safely.

[DanStokes]

As far as the tach calibration: lacking your skills I bought a tach calibrator box from Dakota Digital. It took a bit of fiddling but I got the Volvo tach to work properly with the 347. Basically, it's designed to calibrate anything to anything. Worth a look.

Dan

[Beagle]

as you well know, I suffer from "analysis paralysis" ... so I would suggest you go for the 4" down pipe now, and split it for 2x3" with one of these
cuz you know you will change it later. Is there room for it? Could always put a cutout on one of them if you start getting too much drive pressure.

https://www.summitracing.com/parts/f...ent=Flowmaster

[TheSilverBuick]

A stack of parts showed up this week. I picked up a set of 3" exhaust tail pipes. I want to run the exhaust all the way out to the rear. I'm not sure yet if I want to neck down to 3.5" on the down pipe then 3" just before the rear axle or go down the 3" at the bottom of the 4" down pipe and out the back. Folks say at my power goals I'm likely fine at 3" after the down pipe, but I'm weary.



I mocked up on the left side, but I will be using the right side as I have all the fuel system running out the left, plus the turbo is on the right.


I got a custom harmonic balancer put together. An engineer I know did the fabrication of an outer ring and a bolt on weight for his car to match the OE 4bbl balancer that is near impossible to find (can't even find a picture of one on Google!). But he never got it put on a center hub. I had Dampener Dudes in northern California put it together for me. I need to find the allen bolts and bolt it into place. I may have issue now with my crank trigger wheel. I need to check the diameter and may have to do something different. Worse case I used my 1bbl balancer for the duration of Drag Week. Dampener Dudes did a fantastic job. Lined up the timing marks perfectly.



I also got an LED display to put in the hood tach housing. I tested the LED display in my Skylark. It was reading about 4x more rpm than it was running, so I think I need to make a reference/pullup circuit for it to make it read right. I'm slightly concerned it may refresh too slowly to be of any real use, but I'll reserve judgment until I get the reference circuit complete. It was only $10, so not big loss if it doesn't work perfectly. I'm thinking of wiring it into a 3-position toggle switch and be able to switch it to display MPH as well. I'm also going to put some indicator lights in the housing, like a shift light, check engine, etc.


I also got in a 250amp fuse and case I need to wire in at the back of the car, as well as larger ground cable, so I need to re-run the ground cable. The engine bay looks so empty without the turbo!

[TheSilverBuick]

It's definately not how the factory did it. I reversed the cooling system to keep the iron head as cool as possible as an added measure to stave off detonation. There is no thermostat in the housing where the OE water pump used to be, the outlet just made a convient hose connection.

The original thermostat location is at the top of the cooling system in the cam housing, I have a plate sealing it with a removable plug to vent the the air bubble at the highest point in the cooling system. Nifty enough, with the engine off I run the pump at full speed, top off the radiator, vent the air bubble, top off the radiator, cap on, done. Minimal air in the system. If any bubble gets trapped in the cam housing its not a big deal, the heat is in the head, the housing is aluminum to disappate heat and will be under the most pressure coming off the pump.

[BlueCuda340]

It looks like you have a reverse cooling setup there, is that right? Enters in the head and goes out the t stat housing on the block? Any concern with air aboe the inlets on the head? Or is that how the factory did it. I look forward to seeing it at drag week!

[TheSilverBuick]

Pretty much have the cooling system revamped. I need to cut a small section of 1.5" exhaust pipe from my scrap pipe bin to connect the lower radiator hose, but otherwise is all plumbed in. Now I need to dust off the Jeep solid state fan relay I bought for the water pump and wire it in so I can control the water pump speed. I had the old pump setup as ON/OFF depending on throttle position and coolant temperature, but with nearly tripling the water flow I do not think that method will be appropriate. If I can slow down the pump down by at least 50% I will be happy with that.


I'll redo the lines going into the head when I actually bolt the turbo back in. I will likely try and find some 1" pipe to use to keep the rubber lines from the exhaust heat. Or a bunch of zip tied rubber line....

[TheSilverBuick]

The progress continues. I ended up bringing the machine shop a spare cylinder head the following day because I need about 0.10" worth of valve reliefs cut into the pistons to maintain the non-interference design and they needed a head to get the proper angle with the valve size. I finished running the ground cable to the front, but I think I'm going to re-do it at a later date. I will see if I have any starter cranking issues first. I ordered a 250 amp fuse and holder to set up on the power side incase the main wire shorts out some how.

Made a simple upper radiator bracket. If I need something more substantial I'll change it, but I think it will do just fine as the upper radiator hose holds it in place pretty well. I also trimmed about 2" off the fan shroud to use my electric fan set up. The 2nd generation F-body radiator is narrower than the 1st gen.


I pulled the turbo off so I can start on the header work. I also started on the water plumbing. Because the radiator has a heater hose port I do not have to do any funny plumbing for the heater core. I'm going to get some heater hose from the parts store today and finish plumbing in the water pump. I need to wire in the PWM controller so I can control the water pump speed, then I should be pretty much ready to put the car back on the road.


The old 3-core was in pretty rough shape. Kind of hand an overheating hiccup a long time ago that bulged out the cores.

[silver_bullet]

Pretty!

[TheSilverBuick]

Some people are weirder. This Alfa engine inline six is sitting in the machine shop lobby waiting to get dynoed.

[silver_bullet]

I have a 292...could I be a weirdo too?

[STINEY]

Yeah, but he's OUR kind of weirdo.

[JOES66FURY]

Weirdo.

[TheSilverBuick]

People say that you will get more rpm out of a 230 because both the 230 and 250 use the same size valves so effectively gets choked on the longer stroke, but for the few on the dyno, displacement wins in power. People put the 292 crank in these for a bit over 300 cid. They cap out around 5,000rpm but make more HP than the 250 or 230. I contemplated going that route. I've also contemplated going the 230 route because I have a handful of them now.