408 small block street build

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ap6street

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Currently i am running a small stroker in my abody australian valiant . Was wondering what people think of the build and where could improve.
Mostly street car but a weekend thrash around and take to a few shows.

360/408
Scat crank rods
10.28 comp
Indy 360-1 heads. Non ported
Solid roller 245/245 612/612 108lsa 102.75icl
Ivc 45
1" spacer
1050race q quickfuel
34 degrees total
1 3/4 triy headers
2.5 exhaust
3600rpm 10" converter
4.10 rear end dana 60
Leaf springs
26.8" rear tyre
 
Had on a dynanometer dyno . Made 350rwhp . Not sure how that would transfer to flywheel. No track yet as its closed atm where i live. Seems bit sluggish in 3rd mid rpm.
 
Those indy heads dont go alot un ported. Have them ported, deck them to raise the comp a bit and add 15 degrees more duration on that solid roller and you will gain 100 hp at the wheels
 
How much comp will i need to run a 260 cam though ???

And then ill probably run into ptv problems.
Unless i take apart the bottom end to notch the pistons.

Currently have .110 and .200 exhaust.

Would i gain much with a full cnc and a mildly bigger cam
 
Power as is seems a bit low. That's somewhere between 430-450 flywheel hp if the rw figure is correct.

Comp around 11 will be fine enough.

Fully ported heads and a bigger cam should see 600 hp from that combo.

Would be great to have some drag strip mph to guage where you are at

I cant see ptv being a problem. Do you pistons already have valve reliefs?
 
has,reliefs,in,the,pistons,already,yes.

what,does,the,bigger,cam,profile,go,like,at,low,rpms,ie:street,driving???
 
When i built the motor i wasnt looking for big hp (600ish) i got the indys fairly cheap in the kit.
Obviously some track time here would be of most value but i know of 2 other cars here in adelaide with back to back dyno figures with considerable losses.
720-515hp
605-394hp
But i tend to agree mine is probably lingering around the 450 mark especially because it seems to have the go down low.

Without doing the obv of cnc ports big cam and big comp.
What sorta suggestions for maybe getting it up to 500hp or 520.
Worth getting the heads flow tested as is or get them ported even without big cam and comp ??
59cc chambers atm so probably wont get the comp up much more without pistons .
 
If the heads flow decent I don't see any reason at all that it won't make 525+ hp with the combo you have now, properly tuned of course. I'd start by yanking the heads and have them flowed to see what their actually doing. Sounds to me like something isn't doing what it should because if the dyno operator figured the correction correctly it should have made way more than 350 rwhp. This is where a time slip would really come in handy
 
To add to the suggestions, better/larger tube headers.
 
Love to know the cranking compression has to be pretty good. Ported strip dominator or victor in addition to head porting and better headers
 
Thanks for the ideas everyone. Probably pull the heads and do a flow test and get them cnc ported.
The headers were 3200$ custom to fit the rhd model, ao wont change them out just yet.
Not sure if i mentioned but would a slightly bigger cam help. Dont want to change bottom end just yet for comp and valve reliefs. Or should i just try the heads first up??
 
Thought i would update an old thread.
motor had some dramas so pulled it out and thought id change a thing or two, in the end we changed everything.
new h beam rods, flat top pistons
custom solid roller 266/272 110 .660 camshaft
cometic gaskets , getting us around 12.8:1 comp
ported the indys and manifold , flowed just under 330 at 28"
new crane lifters
KB custom carburetor
i think we kept the block, crank, heads and oil pan.

been a year almost in the build , engine dyno next week im hoping
 
ap6street said:
Thought i would update an old thread.
motor had some dramas so pulled it out and thought id change a thing or two, in the end we changed everything.
new h beam rods, flat top pistons
custom solid roller 266/272 110 .660 camshaft
cometic gaskets , getting us around 12.8:1 comp
ported the indys and manifold , flowed just under 330 at 28"
new crane lifters
KB custom carburetor
i think we kept the block, crank, heads and oil pan.

been a year almost in the build , engine dyno next week im hoping
Click to expand...
Sounds good. Should go around 600 at a guess
 
yeah hoping, guy doing the dyno thinks the headers might hold it just under.
they are pretty avg shaped tri-y 13/4 -21/4 - 3"
but will find out soon
 
Sounds like you just threw $5000+ into this motor... why not pop for another 800 for the right headers?
Im rounding up for Aussie dollars...lol
 
mbaird said:
Sounds like you just threw $5000+ into this motor... why not pop for another 800 for the right headers?
Im rounding up for Aussie dollars...lol
Click to expand...

A few posts back he stated he has already paid $3200 for custom headers.
Lots of 10 sec cars here with 1 3/4 pipes
 
IMG_4145.jpg
 
yeah hopefully engine stands strong and i will be very impressed. had i known i would change so much probably would have went for an r3 and some w789 heads. or maybe try fit a bb though.
 
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