19 replies to this topic

[S pack]

tell him to buy a chev
"you want it to rev buy a chev"
that said why does he want 8000 rpm anyway?
without head/cam/manifold work it won't produce power at those revs anyway
another alternative is to chase up a old v8 supercar race engine they rev to 7000 all day....

^^^ Nah, get an old Ford Escort 2L ohc, they rev to 7000 rpm in factory trim no probs. Mightn't have the grunt of a V8 but it will rev.

[Struggler]

I'm pretty sure the RVK355 burnout VK Commodore from SA used a stock 304 short for a while.

He fitted his ported VN heads with a 288 Crane and a Harrop intake.

Was limited to 8K or similar and lasted a while.

I'll see what I can find.......

[Struggler]

Here you go..... http://www.aussiev8....04-max-rpm.html

The real limiting factor is the valve springs. The fun stops when a piston and valve meet at 8K.

[Struggler]

Properly prepared I would be confident the stock rods and crank will go the distance.

He will need to fit flat top pistons to get some comp up anyway.

[76lxhatch]

A standard 308 will happily rev to 7000 with a bit of a cam and some decent valve springs. Insurance in the fastener and oiling system departments is a good idea, but then again if its going to see lots of abuse and blow up anyway you may as well keep it cheap. 8000 is another matter entirely...

[ozyozyozy]

I agree with 76lxhatch.
7000rpm no prob, vn rods, factory crank.
8000rpm, whole other prob, requires ALOT more effort, especially to make it reliable.
Old group A engines used to rev to 8500rpm in race trim and 9500 in qualifing. They had problems with the blocks cracking, rear main cap fally out.

[Punchy]

Why stop at 8000 rpm if he's doing it for the sound of it..

9000 soulds like its made from alienware and makes your face go 0_o <- boggle !

There was a orange hj sedan a few years back that used to goto the drag here in queensland to Willowbank.
It was a nitrous jobby thing too.

He used to sit on the start line and wind that thing up, and drop the clutch for launch, Just like them guys used to in the early days of rotarys on the start line.

Seriously everytime he did a burnout it took a month of sundays for it to come back into the "normal" sound realms that people associate with hot 308's.
i have no idea how long those engines lasted for ...But Either way im sure your mates spare parts and scrap metal bin will see some good use shortly if he wishes to persue this line of thought.

[Shtstr]

As staded before the 304/308's have a few down falls when asked to proform. The thing to remember is your engine is an air pump and thats what you need to look at is cam valve springs rockers porting carb/efi flow con rods main studs head studs main's to 4 bolt with gurdle. Ballace everything. You can restrict the oil to the top end by blocking push rods and useing spray bar on rockers and springs.
Next thing you have to look at is driveline and gear ratios.
No point haveing an engine that can spin to 7000+ if you have 2.6-3.08 diff gears.
Last one i built had 4 bolt mains longer h beam rods 6.0" forge pistons to suit roller rockers & lifters rev lit from chev modified to suit extesive head work and larger springs and 10deg valve spring locks.
By changeing the rod length yo increase torque. and reduce wear and stress on te rotating mass.

[Shtstr]

sort of but they only use the short rod and it's not the best option only the cheaper of the 2

[myss427]

You want to run the longest possible rod and short piston, more dwell time at top dead centre and less piston to rod angularity. But you need to spend up big! As said, you go 7000 pretty easy but 8 or 9000 is another ball game. Look at NASCAR engines that still go bang every now and then, they cost $70 - 100K. Yes you can build one cheaper that might hit it for a milli second but you'll be on borrowed time and you will not do it under $20k