Some burning questions about upgrading shocks

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RC Newbie
Hi everyone.
I've done my best to find this bit of information but have came up empty. I have a HPI Trophy 3.5 and parts are becoming rare to nonexistent after they discontinued the buggy. Here's my questions

Do shocks have a standard size for the mounting holes or will they only fit specific cars?

The Trophy Buggy Shock lengths are 97mm/112mm, if shocks generally mount to most vehicles do I need to look for exactly 97mm/ and 112mm? Or could I use 100mm/114mm shocks, kind of staying 2÷3mm range within the original size?

I'm sure the answer is out there however I've not found it so it's just time to ask.

I do have a engine swap/upgrade question. The trophy is a .21cc, would any .21cc engine made for a buggy mount? I know there's the engine subforum for this but for time sake i have to toss it in.

Thank you!

Lazy Bushman

RCNT Qualifier
RC Driving Style
Some manufacturers quote an over all length and some eye to eye. Just make sure you measure yours the same way. A couple of mill shorted is ok but the the HPI’s compress a fraction on install then you might need to fiddle with things like turnbuckles, wheel towing extra but nothing major and you could well be fine


Dekalb, IL
RC Driving Style
As for the engine, pretty much any .21-.32 big block nitro engine will work. They all have the same bolt pattern for the crank case. The only thing you may need to be aware of is the starter housing size. Some are larger than others and some mfr's use lower engine mounts so the truggy/buggy can be used with a starter box more easily. In that case, to run pull/roto start, you need taller engine mounts to raise the engine up so the starter housing clears the chassis.