Comp. Check. Have I got this right? 3400 hybrid

[Bridgetown]

I am trying to figure out my compression using the calculator. Just want to make sure I have the figures right.
Specs:
3400 Block (stock bore)
3500 Heads
ROL 3.4 Iron head Graphite head gasket
Speedpro hyper 3.4 Iron head pistons

Coming out to 12.51:1 I didn't think it was going to be that high. Is this setup tuneable on 92 Octane?

[Bridgetown]

50 views and no replies? C'mon, help a brother out.

[ericjon262]

assuming all the specs you put in are correct then, yeah that sounds about right.

[Bridgetown]

That's kinda what I wanted to double check. I read that this setup would come out closer to 12.3:1 Is anyone on here running this combo?

[bob442]

There is one person iirc, if I was concerned about cr being to high I would mount the pistons on a lath. And give em a bit if a dish. I'm running 11.5:1, not to much spark retard, but it does not like anything lower that 91, and oh hell does it love 110!

[Guest]

it will need 93 minimum probably with some torco added to be safe. A lot will depend on your cam and how much bleed off there is. if its a tight cam, then you could see some preignition. You might have to adjust your tune for less timing unless you run some e85. if you run e85, then that engine will run great.

[Bridgetown]

What do you think the highest compression you could run for a 3400 on 91 octane? 93 is not that common around here.

[3400-95-Modified]

I would stick it at or below 11.5 if all you can get is 91...

[Bridgetown]

I would stick it at or below 11.5 if all you can get is 91...

In the opinion of more experienced 60* builders here, what makes more reliable power (tuning aside), mild boost or high-rev/high-comp.?

[ericjon262]

In the opinion of more experienced 60* builders here, what makes more reliable power (tuning aside), mild boost or high-rev/high-comp.?

too many variables to say, it depends more on the quality of the build/quality of parts used.

[Bridgetown]

Assuming both were built with the best possible parts. With a target of say, 300 Crank horsepower, which is the more reliable way to get there on a 3400engine?

[ericjon262]

I would say boost.

[3400-95-Modified]

high-rev/high-comp.?

It would have to also include Large cam to get to 300 crank HP... and LOTS of porting.

[Bridgetown]

It would have to also include Large cam to get to 300 crank HP... and LOTS of porting.

Naturally...

[ericjon262]

It would have to also include Large cam to get to 300 crank HP... and LOTS of porting.

Lot's of cam, and poor street manners, I again, say boost is where you should go.