I don’t know the ramp skin gauge on my -8, it’s whatever was standard on a 2004 vintage QB kit... I had multiple ramp cracks within the first hundred hours running a 4 into 1 exhaust pipe with no downturned tip. I stop drilled the cracks, laid patches over the top, then installed a downturned exhaust tip. No more cracks at 1800 hours.
For those still building, consider replacing the provided aluminum cooling ramp with 0.15” SS. This also complements firewalls insulated with Fiberfrax and a thin SS clad.
Use the provided aluminum cooling ramp as a template to fabricate this SS replacement. It only takes a few minutes to get the curved front end just right.
Carl
For those still building, consider replacing the provided aluminum cooling ramp with 0.015” SS. This also complements firewalls insulated with Fiberfrax and a thin SS clad.
Use the provided aluminum cooling ramp as a template to fabricate this SS replacement. It only takes a few minutes to get the curved front end just right.
Carl
I saw someone had created an insert for their tunnel and I decided to do that. I believe I used .032, bent the flanges on each side and tapered them toward the rear to match. I installed it right over the existing tunnel, prosealed the front on the firewall and riveted it in place. It greatly reduced the drumming and so far no cracks.