The rebuild continued....
With the unexpected delay waiting for the heads, time was spent painting everything that could be painted.
The new heads were checked and fitted with considerable attention to detail, checking seat pressures, push rod length and valve to piston clearance checked. Although it would ultimately take longer, the inner valve springs were removed to break in the cam.
With the heads and intake manifold on, oil flow and pressure tested and all good running at 40 psi on the bench. Starting to look almost ready to go back in to the car....
Attention turned to repairing the cast exhaust manifolds to remove a broken stud and repair a broken bolt hole.
The big day arrived and the engine was going back in, albeit with a much smaller toy engine hoist than I used to remove the engine at the farm....
What should have been a very good news day turned out to be another problem. The bonnet would not close without catching the air filter and carb. This was quite annoying as that concern was raised really early on before the air gap intake was purchased and we had reassurance from the supplier it would fit a standard 454 bonnet.
Loads of options were considered including trying to source a larger original L88 style bonnet but they are either very expensive new or extremely rare 2nd hand, as well as getting an aftermarket scoop/bulge and remodelling the bonnet to an L88 style. We also, rather drastically, considered cutting a hole in the bonnet. In the end we opted to use a original GM LS6 aluminium intake to keep the overall stack height down and retain the standard bonnet profile - this is something I already had available as it was fitted last year to replace the cast intake when the Holley 750 carb was fitted, just before the engine went bang.
Intake swapped over and carb refitted, the bonnet closed and things were looking very good.
On investigation before the engine was fired up to run everything in it appeared the carb was not opening up to full throttle due to some limiting factors. First of all the accelerator cable clamp was too close to the lever and required an adapter bracket to be made up. More importantly and less obvious was that the movement of the secondaries vacuum controlled arm was restricted by the spacer plate fitted by the previous garage that worked on the car. The carb was removed, plate modified and refitted and all appeared ok, with full throttle working as expected.
The engine fired up first time, and the cam break in began. All looking great so far.
Yet another good news bad news day though. A vacuum leak was traced back to a crack in the carb base which appears to have been caused by a slightly warped base plate. The repeated fitting and removal over probably added to this fault, but the end result is a carb that needs to be replaced. Contingency fund raided again and a new Holley 4150 Double Pumper 650 CFM 4-Barrel Carburetor 0-4777S and new Holley Phenolic spacer was ordered from the USA resulting in another delay.
With the cam break in complete the double valve springs were fitted.
New carb fitted, bonnet closure checked and the tuning work done.
After almost a year off the road, she is done and ready to drive. Most of the delays arose early on before the car even got to Stubbs for the rebuild as I tried a top end rebuild first, hoping that it was not as major as it turned out to be.
The first drive home was simply incredible, despite needing to be gentle for the next few hundred miles. I have already done 150 miles over the first weekend home, and the engine feels so much better than it ever did. There is plenty of power when needed, even without stressing it too much yet and it's very pleasurable to drive on country lanes, motorways and in traffic holding good oil pressure and steady temperature even with the high ambient temperature over the weekend.
Dan at Stubbs Racing Engines in Derby has done a fantastic job on the rebuild and kept me fully informed all the way through the project sharing good and bad news in a very positive manner, always providing solutions rather than problems which helped to keep my spirits up. His attention to detail is exceptional, spotting and correcting any issues found along the way.
Thanks also to Mark at Performance Unlimited for helping to source many of the parts that were used and offering advice where needed.
Just another week or so running it in then it's due for an oil and filter change and I might think about taking it to a dyno to see how much power this thing has now.
Hopefully we will be at the Nationals this year....
