Structural Question, crossmember bolts in sheer or tension? Options

[cooler]

hello 914 structural experts,

I am planning to create a new crossmember to stiffen rear suspension and support engine. The 914 rear suspension console is well known to flex under racing stress and was reinforced by factory racing teams. I intend to address the flexing issue and create engine (Audi V8) mounting locations with a new crossmember and diagonal tension members. The attached photo shows the location of crossmember (red) and diagonal tension members (blue).

The crossmember spans between the suspension consoles, on center with the trailing arm pivot axis. The diagonal tension members span also from rear suspension consoles to firewall, near center tunnel. This assembly will need to be removable to facilitate engine removal and is intended to stiffen the entire engine bay/rear suspension.

I am struggling with detailing the crossmember bolted connections at suspension consoles. I assume each connections should include two bolts each but, should the bolts be loaded in shear or in tension? What size should the bolts be?

Thanks in advance

[cooler]

Hello Again,
Thank you all for taking the time to respond.

I have studied cars with removable subframes/crossmembers. The intent of how the loads are transferred are not always clear, sometimes rubber isolating mounting points are used. My intent is to stiffen the chassis, to maximize stress transfer no rubber insulators will be used at chassis connections. The engine however will be mounted to crossmember via rubber mounts.

I'm also thinking the load created by the engine are minimal when compared to loads transferred from the suspension. The engine loads are proportional to engine mass. The suspension loads are proportional to total mass of car.

The members must be removable vertically to facilitate engine removal. I believe if the fasters were also aligned vertically, hole alignment and reassembly would be easier. I also believe that would load the fasteners more significantly in shear if vertical load from the engine are considered negligible. Shear loads on the bolts could be reduced or eliminated by dowel pins in the connection. I have seen old school hot rod crossmember connections made with flanged connections but, they are likely not typically removable. It would be a PITA to align those bolt holes on reassembly.

I may have answered my own question but, I have one more! What, from a seat of pants perspective, to make you feel comfortable, should the crossmember be constructed of.

Thanks again