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LM7 5.3 L LS (cast iron block) fits within the allowable CC range but you quite often see people putting 5.7L and 6.0 L LS engines. I used the weights from the sedan with the hydromatic.

Apparently some people have been known to bore the 5.3L out to 5.7L as it is the same block. I would never do such a thing though………..

For the record


FB ute fixer upper, EK van on rotisserie

TAZ wrote: Thu Sep 04, 2025 6:44 am

Apparently some people have been known to bore the 5.3L out to 5.7L as it is the same block. I would never do such a thing though………..

Over here they bubble test them ......... I was hoping to do the same with my 57 , it could be licenced with a 396 but it was a 540

When I engineered the wagon, the block number was checked. It is a 350 block, with a 327 crank. It was suggested I needed to pull a head and demonstrate it was a 327. I supplied the build sheet, and the engineer recognised the builder and trusted him from past experience.

This kind of experience makes me think more like Smokey Yunick, and hence this thread. If I can demonstrate compliance, my life is easier.

Cheers,
Harv

Question for Harv - I am preparing an application to get the rattler legally licenced - its still got a grey in it according to the rego papers- I need the GVM of an FB sedan, any ideas mate ????

Blacky I just looked at the application I put in when I built Frank and I listed the GVM as 1125kgs

1125 apparently for a Ute mate 1131 for a Sedan this is what Google says mate

FireKraka wrote: Tue Apr 28, 2026 1:45 pm Blacky I just looked at the application I put in when I built Frank and I listed the GVM as 1125kgs

That would be the tare weight wouldn't it mate ? Empty vehicle with 10l of fuel only ?

GVM includes passengers and luggage and a full tank of juice.

I listed the 1125 on the application for both and they never queried it mate

FireKraka wrote: Tue Apr 28, 2026 3:04 pm I listed the 1125 on the application for both and they never queried it mate

I will run with that then - or just make up a number

There is no official GMH GVM for sedans or wagons. Only the commercials had the plate in the engine bay which listed it.

As a good estimate, the kerb weight is 1131kg (workshop manual). Add five adults at 80kg, a kid in the front middle seat (40kg), two cartons of VB in the boot (30kg) and 10kg of assorted Nasco accessories to give about 1610kg.

Bear in mind when one has added a ludicrous amount of motivating force, the authorities tend to start getting anxious about power to weight. More weight, more likely to meet the guvna’s expectations.

Cheers,
Harv

Yes and as i recall as soon as you introduce forced induction the allowable cubic capacity goes down.
Here in NSW
Vehicles > 1100kg:Naturally Aspirated: Original mass (kg) x 5.0 = max. capacity in cc.
Turbo/Supercharged: Original mass (kg) x 3.00 = max. capacity in cc.

From memory my sedan was 1121kgs, x 5 = 5600CC = 341 Ci hence the 327 chev limit.

So for forced induction use this calc on 1121kgs x 3 = 3360cc = 205 Ci.

Whats the weight of the sedan, add 35kgs if its an auto ?, maybe WA has a different calc.

Greg

Same calcs Greg, a blown 202 JUUUSSSSTTTTT scrapes in

Bastard rules - an LS is 5660 cc, misses out by 60cc or 2 shots ...................

Blacky wrote: Tue Apr 28, 2026 9:39 pm Same calcs Greg, a blown 202 JUUUSSSSTTTTT scrapes in

Bastard rules - an LS is 5660 cc, misses out by 60cc or 2 shots ...................

one thing lucky in NSW it's just a guidline put anything you want in as long as you satisfy the engineers requirements

Paperwork submitted - wheels, tyres and track is going to be my biggest issue I believe - front is over track , rear is under.......