As some of you may already know, I am in the beginning stages of building a replacement Nailhead for the GS. Still trying to wrap my head around everything and figure out the best way to go. This will mostly be a street car that will be taken to the track from time to time. The car currently has a Pertronix Ignitor in the distributor and a Flame Thrower coil. That is how I got the car. For this new build I am trying to figure out if I should just go back with the same thing, or if I should upgrade. The engine will be a 401 bored over the minimum amount to clean up from the standard bore that is in it. I will then be ordering a set of forged pistons from Tom to get a true 10 or 10.25:1 compression. For now I plan to run the 091 style cam offered by Russ, stock manifolds, stock heads, and a Q-Jet setup. From there I will eventually build a set of headers, and do some benchwork on the intake and heads. Anyones help and experience would be greatly appreciated.
I've got a Pertronix Ignitor III and have been very happy with it. It has multi-spark, and a built in rev limiter. Pretty cheap too! :TU:
On my blue 66 gs and other cars. I run a msd distributors and a 6al2 boxes. I've had pretty good luck with msd and the distributor is really easy to recurve to what you want. I had a couple of problems with the distributors corroding under the cap. But they took care of it and replaced the bad parts. They say they've fixed that problem on the ones from 2008 and newer. My dad, he runs petronics on his gs's and has had really Goodluck with them.
Johnny, I put one of the earlier Pertronix ignitors in the GS back in 1999 then switched to a Crane 750-1710 in 2006 when I rebuilt a distributor from a dual quad engine. I just stored the distributor with the Pertronix and used it for the engine in the Special in 2008. I have had no issues with either one. I remember the Crane being a good bit easier to install than the older Pertronix. Don't think you'd go wrong with either one, but had not seen the Crane mentioned. Thought you might want to check it out. Steve
Thanks for the input guys. I like MSD but there stuff is a bit pricey. For good reason I am sure. I am leaning more towards the Pertronix Igniter III. More so because you maintain a stock or factory look by not having to run a box, but you get some extra benefits similar to the MSD. Steve - Thanks for the input on the Crane. I had not seen that one yet. Ill do a little looking into it as well. Keep the suggestions and experiences coming.
I run the Ignitor III and flamethrower in all my stuff, with a dedicated 12v through a Bosch relay. Never had a problem, and the rev limiter makes me happy. Two cars came to me with Igniter I's in them that were probably 10 years old and working fine. My 73 came to me with a Stinger S-4 set up in it, direct from Kenne Bell back in the day. I pulled it out because I thought it was causing issues, but it wasn't the problem. I kept the whole system because it intrigues me, the way it pulls out timing at the top end, and the KB guys swore by them. They still bring decent money, although people have said they don't create the strongest spark. Maybe someday I'll throw it back in and mess with it.
I've been using the Breakerless SE. Been installing & selling for more than 10 yrs. now with no complaints or comebacks. Tom T.
I run a ready to run msd distributor, msd 6btm box and blaster2 coil and love them. ran a pertronics and I loved it also. The gain you will get from the MSD is so minor for the type of build you are doing is it worth the $700-800 cost for the msd setup compare to under a $100 for the pertronics. I use it for my turbo setup but that's to pull timing out with boost. Paul
My blue car has a Mallory Unilight with a MSD 6A box. Mech advance slot was welded up to limit advance to 12 deg initial and 32 deg total. Been running great since the 1980s!! For the red '66 I put back together around '09, I went with a Dynaflow distributor (same mech advance as the 2x4), points, and a Mallory 685 box that was $150 from Amazon ($290 now!). The Mallory box has lots of options such as programmable retard, rev limiter, and rpm activated switches for stuff like a shift light for the 5 speed. I was going to go with a Crane XRi points replacement, but they weren't avail at the time. It has a rev limiter which is a nice feature for a stick car. One of the Petronix setups has the rev limiter too. Keep an eye out for a '63 & earlier/Dynaflow distributor for the 12-32 degree mech advance..... Couple of guys like the one-wire points replacement from Lectric Limited.
Will a Nailhead run ok on today's pump urine with that much compression? I'd have expected detonation on pump premium...but what do I know?
Johnny,,, on a street driven car in Houston,,, stick with the stock compression..... dont boost it.... advertised 10.25 to 1 actually works out to 9.25 to one which is just right.... if you go higher than that you are going to find your self stuck in a traffic jam, 4 lanes deep , on a hot summer day that is 105 in the shade and the cat pee gas is going to ping with higher compression ..... and on that subject,,, in Houston , too much radiator and fan aint enough..... I know because I ran my original 401 /64 skylark there and it took a HD 4 core rad and a 7 blade fan with a fan shroud to cool it.... the Gulf freeway was murder..... also you need a real good trans oil cooler..... but back to your question,,, on a street car, what you already have is very adequate ,,,, guys can waste a lot of money on ign. set ups for the street.... and all it is is ''wow'' stuff.... a stock dist. with a pointless system /advance recurve/ and a good cap and rotor with BRASS terminals, like accel or mallory, or msd and good set of wires/plugs (autolite/Motorcraft) will be a really good system..... because a nailhead doesnt turn but 5500-5800 rpm and very little of that on the street.....on the street 4000 or less..... In all out competition, still the same rpm band.... you dont need a system set up for 8000 rpm..... you just need a good strong spark at the right time.... any thing more is wasted money.....
Schurkey and Doc bring up good points. With a mild cam like that your DCR will likely end up close to 8.25:1 at 10:1 static, and almost 8.5:1 at 10.25:1 static. Not exactly ideal for a iron headed motor. Something around 9.75:1 static will keep your DCR in the 8:1 range. Of course that all goes out the window if you ever put a larger cam in the motor. Check out this graph originally posted by Cheryl.
I run a MSD distributor with a MSD stock-type coil on my 425. No fancy control box. I probably would have bought a breakerless setup from Tom Telesco if I had known him when I installed the engine. The MSD works fine, and the red color matches the '66 425 red engine. :grin:
When talking to Tom about the pistons he suggested going with 10:1 compression because thats about as high as you can go these days on regular fuel. I may just have to break down and decide to run octane booster. I really don't want to run less than 10:1. This is going to be a weekend cruiser and not something driven daily. So having to add booster to avoid pinging isn't that big of deal.
I totally hear your guys concern about my compression being too high, especially in the summer months. My car has AC so I already have the 7 blade fan. The AC system isn't hooked up right now so its not adding any heat to the system. But when it was hot out, in the 90s, I did take the car for a few cruises. It was freaking hot. Praise the lord for vent windows. Anyway, the car hung around 180F maybe 185F. Even sitting in traffic it didn't climb much above that if any. My next question to you guys now since it was brought up. What cam would you recommend to help with the dynamic compression? I don't mind going a little bigger on the cam, but it doesn't need to be completely nasty sounding either. And I mean nasty in a good way, lol. I have tried looking for videos on YouTube of Nailheads specifying what cam they are running and they are pretty limited. In fact only one I find is the Thumper like Andy's running. Your car sounds awesome by the way. Just may be a little radical for me. Also I don't know how they perform either. I hate all these decisions. Hahaha
OH, you wanted the engine RED John???? LOL Now this is just my opinion & I know that everyone has their own. Now past that. The best "Nail" I ever measured was about at 9.75-1. That was with the piston in the hole an average for all eight at .043". Mostly "Nails" are around .055" in the hole. This works out closer to about 9.6/9.65-1 or so. Here's another area of interest. If you measure the in the hole distance of all eight holes you will see that they are mostly all different. And, if you measure, where you are supposed to, over the pin, you will more than likely get a different reading front or rear on the same piston. So it needs to be averaged out. Except in the beginning yrs. of the "Nail" they were not known for detonation/pinging. If the rubber stop rotted/fell off under the distributor advance or you cheaped out & used regular fuel. I feel that because of the design of the combustion chamber being a "Pent Roof" design we can get away with it. As long as the advance curve isn't too aggressive & you can get reasonably good fuel it should be OK. I know about the "Cat Pee" that's available today & I agree. But, a lot has to do with the cam also & how well the volumetric effienffcy is. This is also one of the reasons I made the top ring land .300" instead of the stock .200". More detonation resistance as well as being able to customize your quench area, if nec., or a shot of Nitrous or boost. Some of the high performance engines of today mostly have a "Pent Roof" combustion chambers & are running 11.0-11.5 compression ratios, but they also have aluminum heads/& or blocks with computer controls. Doc, you confuse me, & I'm sure others. I know that stock they are supposed to be 10.25 & we know they are not. Where did you come up with 9.25??? I've measured quite a few & unless your running composite gaskets they are ALL over 9.5-1. But, if your using shim steel head gaskets you have an option of changing them to composites & losing approx. .44-1. This all goes back to distributor advance curve/ & or cam design. Talking with some experience. On my friend's Henry J with a "Nail" in it. We have about 10.2-1. He FLAT OUTRIGHT REFUSES TO RUN RACE FUEL. PUMP GAS PREMIUM ONLY. We don't mix anything in with it. In actuality he really can't afford to run anything else. This is at the track & we all know how hot it can get at the track during competition. But also, then again, we have our fuel/air ratio's correct by using heated O2 sensors for our readings to keep track of things. Now this is not a light car, it's about 2800lbs. or so, & we run close to 11.0's. The 10's aren't too far from reach at this time. We get along just fine, although we do have a pretty good cam but an aggressive timing curve. Just my thoughts. Tom T.
Thanks Johnny! The Thumpr definitely isn't mild. But I wanted an aggressive cam that I knew would fit in a stock engine w/o any valve to piston clearance issues, so I could just toss the cam in and go. I got one helluva deal too. It was a royal PITA to tune, but runs like a champ now! Back to your issue. Something like the TA-20 or TA-25 from TA Performance would probably be a good choice. It's still mild, but a noticeable increase over a stock grind. And at 10.25:1 static CR, your DCR would be a pump gas friendly 7.78:1. I think it makes the most sense to go with the higher static CR and slightly larger cam, rather than tailoring your custom pistons for something that might get swapped out for something bigger later on down the road. Just my 2 cents!
Thanks for the additional input Tom. Makes sense to me. Of course I'm a noob but I'm learning quickly. At least I think I am. I will give those a look Andy. I did notice for those cams on the TA site you have to click on the details button and look at each one. The lift they show on the main page for the Nailhead cams is with their 1.6 ratio roller rockers and they figure stock at 1.4. So its a little miss leading at first glance. I do kinda like the looks of the TA-25, 459/479-218/228 on 112LC. Just wish I had a cam to compare it to as far as sound. These cam numbers are still almost a foreign language to me. I understand what they mean but its the putting them into perspective that gets me. And I totally agree that it makes more sense to go with a little bigger cam and higher static CR rather than tailoring the pistons to a cam I may not keep forever. And I could guarantee I wouldn't go any milder than the 091 style. Lol.
Awwww, Tom,,,, You guys know me well enough to take what I say with a grain of salt.....:laugh: and once in a great while , a bucket of salt..... The way I arrived at that figure was a general consensus from machinist and mechanics thru the years that the cr is usually a full point less than advertised ...due to manufacturing tolerances ....simple , huh.....that is why I tell the younger set , that when they start to ''blueprint'' an engine , they need to do it carefully....:TU:
Johnny, As for the sound I might have a video on a old post from years ago with my car idleing with the NH400 cam. If I remember right the NH 400 is a 218/228 at .50 on a 114 with about 480 and 490 lift. Kinda close. Thread was ( 4 speed 66 ). Not even sure if its still out there. Also has 2.5" exh.
