Tommy you will be fine other than maybe Sonoma or Vegas at the end of the year. There is more in it than you think.

Just trying to figure out if I should put that engine in, or leave the Mopar in. It was on a 7.17 pass in Joliet last week.

So just to bring this up real quick again, I have been considering upping my crank size the next time my 565 comes apart as I'll probably need pistons so changing the size then makes sense. What size does everyone reccomend for these heads to make good, reliable power and get me closer to low 4.60 range in Ohio? I've been told 615 is the way to go with less windage etc. and have a good piston in there if I decide to spray some, but there's also the guy's who say go 632 for maximum cubic inch and be done with it. I have a Dart Big M block, and when the time comes also I want to bore the lifters to .904's and do the necessary upgrades to add reliability with big power. I check valves pretty religiously already just because I know the offset lifters can wear out quicker. The heads have titanium valves, T&D shaft rockers so it has good pieces, I still think my cam is off for the head style and cubic inch should make the heads work well. Just looking for peoples advice who have actually used these heads, mainly looking for a fast bracket motor in a 2000lb dragster.

There are some pretty potent 615" combos out there, and they seem to be gaining in popularity. I for one always say go for cubes, but that may not be the standard to follow any more....

That's kind of my point... Unsure of which route to take, especially being the spread port style head. I know of a bunch of 632 spread port motors that just don't seem to perform as well as they should, I have only heard of the 615 stuff the last few years and not sure if it's the better route or not..

and I know a bunch of spread port engines that flat out haul, 3 of which are here right now in Epping at the NHRA Divisional. 615-632's with Brodix 9 degree heads built by APD, running 191 mph in S/C.

Some SR20 doing that to....

I’ve been there when all were at the track on the same weekend and the 9 degree outran them all in mph by at least 2 mph. Currently there is no SR/BR20 headed engine that runs as fast no mind faster in S/C than the 9 degree.

WRONG....KB..does

But he should with 674 cubic inches.

Still SR20...an easier on parts...an much easier to find parts at tracks...an this I know cuz I have both...

my next engine will have 9 degree heads not 20 degree heads

quote:

Originally posted by 1320racer:
my next engine will have 9 degree heads not 20 degree heads

They are badass for sure DUGGINS just built one with a BRODIX X BLOCK...customer went 4.17 pulling 8 degree out for 1.5 seconds....single carb....

So 632 or 615 with my current heads?

Your current heads are not the heads to build a short block around. Sell them/ the engine and start clean with the right heads/manifold for the ET/mph goal.

Cubes
You cant go wrong with either 615 or 632, both work very good. If you were building a specific TD or TS engine and planned on spinning it over 8100 -8200 plus in order to make big power the 615 is a better choice.

Heads - 9/11/12 Degree vs SR20/Pro20
Hands down the both spread port heads will make more power that the 20 degree stuff but it comes at a cost, both added dollars to build these combos and weight, these motors are about 30 pounds heavier apples to apples. Again if your building a specific TS/TD motor with dual carbs and the rest, the spread port is your head hands down. If your looking at more of a bracket deal, cast intake/single carb, typical bracket cam profiles you will be better off with the 20 degree head. The added power between the too is now reduced because you are not using the spread port stuff up to it's potential and even though they will still provide more power in this configuration the added weight will basically wash out the added power.

Pro's and Con's of Both
- 20 degree head combo's cost less
- 20 degree valve train is simpler with no offset rockers that are needed on the intake side of the spread port stuff
- spread port heads have room for a good deal larger intake valves
- spread port heads have raised ports that allow for more air flow and better air flow
- Single carb cast intake weighs 36 pounds for the spread port and 23 pounds for the 20 degree combo out of the box (Both edelbock intakes that all engine builders are using)

The simple fact is once you set the size of the motor and the desired power, that sets the rpm at which you need to turn it to make that power. From there it comes down to selecting the right parts in which to achieve the goal. So let the debate go on.

IMO, if your looking for 1250 or less HP, go 20 degree, over 1250 go spread port! Or spray the 20 degree combo,, LOL!! Both combo's work very well!

quote:

Originally posted by TOP38:

IMO, if your looking for 1250 or less HP, go 20 degree, over 1250 go spread port!

This^^^

I have both a 12 deg profiler headed and 14 deg Big chief headed engine. They both were 615's although the 12 deg is now a 622. Both have made over 1250 on motor only and both have been done into the 6.30's on spray in a 2045lb dragster. I can tell you the biggest mistake i see people making with either of these heads is trying to run too tight of a converter and trying to short shift them. Either of those heads like RPM and mine responds in the time slip every time i raise the shift point and trap RPM along with a looser converter.

quote:

Originally posted by T/D6591:
I have both a 12 deg profiler headed and 14 deg Big chief headed engine. They both were 615's although the 12 deg is now a 622. Both have made over 1250 on motor only and both have been done into the 6.30's on spray in a 2045lb dragster. I can tell you the biggest mistake i see people making with either of these heads is trying to run too tight of a converter and trying to short shift them. Either of those heads like RPM and mine responds in the time slip every time i raise the shift point and trap RPM along with a looser converter.

That's what I'm looking for here.. I have the 14* Big Chief heads already so I don't want to spend more money trying to go another route. I just want a fast bracket motor for weekly races, something where I don't get chased EVERY time I go to a big money race and if I decide to turn it up for a local Q16 or Q32 I can with either rpm or a little spray. We run gas as it is and I have seen plenty spread ports running 4.50's at big money races win the money, so obviously they are good stuff to run.