360ci RAISED RUNNER STEELHEAD ENGINE

[perfconn]

Because 34* makes good power with no detonation and 33* didn't change anything.

[dave brode]

http://www.differencebetween.info/diffe ... -and-steel

[perfconn]

No one is debating the chemistry of a head.The question is about loss of power.Would you rather debate on terminology or try to solve a problem.This is not English 101

[MadBill]

Of the parts changes you mention, I'd say the cam has the highest probability of affecting results. Have you run that exact spec in a smaller bore engine with good results?
Also, although a given head typically flows a little more on a bigger bore, it usually leaves room to step up the intake valve diameter a bit.

BTW, I believe 4.185" is max bore for NASCAR.

[perfconn]

I have run that exact same intake lobe with good results in a smaller bore.How much smaller and exactly how much better it was I would have to look at my Dyno sheets & build sheets.I do know it was with 6" rods and same size valves.I. also believe it had 1.75 intake rockers and this one has 1.80
I thought when they went to the R07 with 4.5 bore spacing they allowed bigger bores.I know I see 4.200 bores quite often.

[MadBill]

High-effort engines like your are of course very sensitive to changes and you have several here, so I'd start by going back to the exact same spec cam as used in your best power engine, starting with the same indexing that worked best on it. .

The RO7 bore spacing was increased for better cooling, but the max piston diameter is still 4.185"

[perfconn]

Thanks Bill.I used the bigger intake lobe than I ñormally use because the shorter rod would need it.I'm thinking it could probably use 4* less on the intake but I'm always changing stuff on every new engine to try and find something.It seems like about 705hp & 535 torque is all I can get out of a 360.I've used one of these topend on a 415 and it didn't make any more power.Ton more torque but no more HP.
I've been wrong before and I'm probably wrong on the 4.250 NASCAR stuff.

[mag2555]

Why the Hell are your air to fuel ratios swinging around by some 20gph at some rpm ?!!!

Man between 7200 and 7400 your going from .23 to over .40, that's huge!

[RCJ]

You when from a 6.00, 530 gram rod to a 5.85, 570 gram rod I would expect lower peak hp from those changes.Were your heads new or refresh?

[Warp Speed]

Maybe I misunderstood, but the op went to a shorter stroke AND a shorter rod?
BTW, the max bore size in cup is 4.185, and a max ci of 358.
4.195 in Xfynity and Trucks with a max ci of 360.

4.195 us about as big as you can get away with in the casting, as even though they have a 4.5bs, they are not Siamese, and have water running between the cylinders for cooling during extreme temps.

[perfconn]

Warp,
Yes I went with a shorter(3.27) stroke & a ( 5.85) rod length & 4* more on intake duration.Looks like it didn't work but don't know why.
RCJ,
Yes shorter rod should have lowered peak torque but I think bigger cam messed me up.
Mag2555,
Don't know why BSFC varied so much but it never got in the twos.Don't have any A/F ratio readings on the Dyno unfortunately.

[DaveMcLain]

Warp,
Yes I went with a shorter(3.27) stroke & a ( 5.85) rod length & 4* more on intake duration.Looks like it didn't work but don't know why.
RCJ,
Yes shorter rod should have lowered peak torque but I think bigger cam messed me up.
Mag2555,
Don't know why BSFC varied so much but it never got in the twos.Don't have any A/F ratio readings on the Dyno unfortunately.

When you added more rocker and more duration to the engine did you run it through some lash loops on the dyno? If so what did that tell you?

I don't think that the differences in the stroke and rod length will make that big of a difference.

[perfconn]

Dave,
Yes tried lash loop but no real changes showed up.I don't think it was any one change.Shorter rod should have lowered peak but maybe bigger cam offset it.I have run 4.185 by 3.27 before in Brodix Track 1 Spec heads and won back to back SRRS regional championships so I don't think it's the bore stroke deal but maybe adding in the bigger cam and shorter rod screwed up something.

[DaveMcLain]

What about the exhaust system used in the testing was it exactly the same? I've seen an old rusty on the inside set of headers take away that much power on a 450 horsepower engine before in back to back testing.

[Tuner]

Why the Hell are your air to fuel ratios swinging around by some 20gph at some rpm ?!!!

Man between 7200 and 7400 your going from .23 to over .40, that's huge!

It looks like you have the time between RPM steps mixed up with BSFC. Where am I missing fuel GPH info? I don't see that.

However you're right, the BSFC is erratic. It is anomalous between 6200 and 7200 and particularly it is crazy between 6600 and 6900 where the power backs up 15 HP and recovers. Carbs with too much air bleed do this if they have too large MAB or too large or too many E-Bleeds.