Isabel FTW!

2013 Fair Haven Fire Company 14th Annual Car Show 10/12/2013. Isabel was awarded Best in Show!

Very nice, congrats on that award. Makes all that work worth while.

Chris

Congrats … She deserve it !!! :ylsuper:

Congrats Bob.

Well don Bob, It doesn’t surprise me a bit.

This is just way to cool Bob…what an honor

Congrats! Beautiful trophy for a beautiful car!

Congratulations to Isabel. I guess you did all right too Bob. :poke:

Thanks guys! A lot of fun and a great honor for sure.

Not surprising at all, e-Bob. :slight_smile:

Now finish up the 408 and go get some Thursday night street fights trophies. :slight_smile:

X 2. :slight_smile: John

Congrats!

Congrats - your car is awesome!

Thanks again guys! 408 build is just getting started but it should be a beast! I also plan to change the cam in the current engine, need more overlap to work with the CR.

Bob, from what I can remember I think your running a 351C with Australian heads and the same cam as Im using as well. What were your findings with this build to make the move to a 408 stroker and a cam with more overlap? It’s good to know in advance of finishing a build, if there can be fixes made as a result of somebody’s own experience.

Correct on my current engine. True 10:1 (which is pushing it with iron heads), custom thicker Cometics head gaskets to get down to 10:1 with the Aussie 302C tiny 58cc chambers. Cam is comp XE262H, dynamic compression ratio calculations show 8.43:1 DCR, 8.0 being the generally accepted maximum limit for pump premium with iron heads (XE262H intake closing is 57 ABDC). XE274H (which was too much cam with only 3.25 gears) has a intake closing of 63 ABDC. This yields a DCR calculation of 8.10. I wanted the XE274 originally but did not have a 5 speed at the time, nor taller gears like the 3.73 and up called for. The XE262H was the right cam but not with that much compression. I have made do by using more carb to try and control detonation. The detonation problem is confined to low RPM’s and is a rattling sort of sound, not like what people usually associate as being detonation. Learned something there - the hard way!

A whole different story with the 408C build - by design. I will be running Trick Flow aluminum heads. The common wisdom is that up to one point higher compression is permissable with aluminum over iron heads. With the custom Lunati Voodoo hydraulic roller I am targeting (intake closing 69 ABDC) and 10.5 CR, the DCR will be 8.16. A good number for aluminum heads (I hope).

Let’s face it, building (or buying for that matter) a stroker is expensive, this is why I avoided it (and the 5 speed) at the outset. I spent a lot of time and money on Isabel, and wanted to use my TL 4 speed and slightly enhanced build from like I had “back in the day”. I did that and made extra work for myself in the process but people who know me would probably say I like to work/tinker so in the end it is okay (I guess!).

A simple DCR calculator can be found here: https://www.uempistons.com/index.php?main_page=calculators&type=comp2, a more extensive one (that seems to yield the same values though) here: http://www.wallaceracing.com/dynamic-cr.php

Long and short of it is I learned that 8.43 DCR is bad news with quench heads with thicker head gaskets (sacrificing “squish” to get lower CR) using pump premium. 8.10 with the XE274H and iron heads will be marginal but should be a lot better than 8.43. Should have stuck with 9.5:1, i.e. used open chamber 2V heads - the ones I have had the best luck with in my history of running Clevelands. But getting to 9.5 with 76 cc chambers and flat tops would not happen unless one can get a thin steel shim sort of head gasket and do some decking of the block.

8.16 with aluminum heads on the 408C should be fine.

This is my current view but I do not profess to know everything there is to know about it all, I am learning though. Life = learn, that is my credo.

Regards,

Bob

Thanks Bob for the info. That is exactly the same build as mine, yet not finished. I do have a 750 Edelbrock and was told I should be no bigger than 650. The only difference is I have 350 gears out back. With the build you have now, you were getting substantial spark knock then? If I were to change over to the XE274H and using my gears would this be better? Im not using a standard, although this would be nice, I have a C6, but thought I would go with an AOD.
Im not anywhere close to being finished with the car and to make the 351C a stroker now would be too much for my $$. What was your experience of the performance of the engine as it is now, even though you have the spark knock problems?

Engine runs strong but is prone to knocking at low RPM and at the equilibrium between accel and decel. Even more so with a 650 CFM carb. Did you get thicker head gaskets? If not, your compression is going to be even more than 10:1. The XE274 will ease the DCR issue as I mentioned previously and that should help - a lot. Depending on your schedule, I can tell you in a couple of weeks when I change my XE262H cam to the XE274H in the current engine.

Now, to be clear, the stroker in an of itself is not key to lower DCR, the things I am doing that will make a workable combination are the right cam overlap/intake closing angle and the aluminum heads (which allows about a point higher CR) - things that could be done to any engine.

Guess what I learned is that for an engine (carb and no computer in the ignition) that will run pump fuel, you cannot run too much compression without having a cam with enough overlap (which BTW is not conducive for low end - the main thing on the street). High compression with a mild cam creates problems.

XE274 and 3.50 gears should be reasonable - but keep in mind Comp says 3.73+. But, what head gaskets are you using (i.e what will CR be)? If you go with an AOD, you can put more gear in. With my TKO600 .64 OD, I chose 3.89.

BTW, I have an AOD core I wouldn’t mind selling, I’ll probably never use it - bought it on a whim. But, shipping something like that would be expensive and a pain.

Ok, I checked the FelPro/sealed power gasket set that i have, # KS 2308 and the head gasket measures .055. It is the thicker one that they offer. I was asured that it would work fine, but boarder line. The cylinders are machined .030 over and they are flat top pistons. The intake is an Edelbrock Performer.
As for the AOD, ya it would be a little pricy to get here. By the way, what carb are you using and what size jets?
Dennis

QFT SS-750 (enhanced Holley) with out of the box jetting.