Short story about your HF dial indicator. I have the same one. Late one Saturday night I was working on an engine and I dropped my good dial indictor that I had for many years on the floor. Broke, needle wouldn't move. Next day I went to HF and picked up one of theirs for $13. On Monday I took it to work to check it's accuracy. One of my responsibilities at that time was calibrating our gauges. Put the HF indicator on a surface plate and measured a bunch of different sized gauge blocks. The $13 HF piece was every bit as accurate and repeatable as the $150 Brown & Sharpe I used at work. Might not hold up to daily use but for what I use it for at home it was a deal.
lol...this is my first and only dial indicator. I love the stupid thing...But I would be a little red faced to bring it somewhere where real machinists congregate!
My original intent for this engine was, and still is, to make the best motor I could out of what is available in self service junkyards. My car is a toy and not a daily driver, so I have granted myself permission to stray from orthodoxy. If it comes to utter ruin and waste, I will consider it all the price for conducting the TRUE junkyard 302 experiment, and anyone who wanted to do their own can learn from my mistakes. Every junkyard motor build I have read in a magazine was anything but a junkyard build. This one is the one I always wanted to read about.....so.....I get to know about it first hand. Now that the disclaimer is out there and clear(?), I must admit that cutting my teeth on piston notching left me somewhat disappointed. While the deed is done, my piston tops cc'd between 3 and 3.4. I am going to remove more material from the 3's until all are at 3.4. .4 cc = about 8 drops of water. At this point, there is no going back because putting new pistons in would cost more than the whole short block cost to begin with. The real problem is what the compression ratio will be with my 58 cc GT40 heads and pistons .020 out of the hole......10:1 with .055 gaskets. A thicker gasket means increasing quench beyond optimum of .035(?), and paying more for gaskets than the short block costs. You may be saying by now...."Spend some money!!!!"...lol, and you would be right. But once you start spending, the money faucet seems to keep running. I think the plan will be to score another set of GT40 heads, and leave the chamber at 65. I have not decided yet. The moral of the compression story is (1) wait until your block is set up and measured before you cut the heads down. (2) cutting valve reliefs do very little to decrease compression.....somehow I just didnt think this through very well. The upside is I have a greater understanding of static and dynamic compression. In my case, it really helps to have a guinea pig on the engine stand to wrestle with this stuff.
From my experience that .035" - .040" quench/squish range that gets thrown around isn't set in stone. I've found that the geometry of the piston crowns have an affect. Some piston tops only have a couple small squish pads whereas your pistons have a ring that goes completely around the piston top. Or at least they did before you cut the valve reliefs, LOL. Also the opposing squish pads on the heads, around the chamber, figure in, too. I've run pistons similar to yours with closed chamber heads at .050" - .055" squish and regular gas without detonation. As with everything in an engine, you have to look at the whole combination.
I have an interest in the trick flow stage 1 cam TFS-51403001. I plugged the specs into a dynamic compression calculator at "go fast math" and it asked for at .050 lift numbers. Their result was a DCR at 8.8 . I plugged the "advertised" specs in another one that had to be downloaded, and was in 3 parts, that said my DCR would be 7.9. I mostly understand how a late closing intake prevents full compression at very low RPM, but 9.95:1 with iron heads scares me. In fact, If I were spending real money on this mess I would err on safety and sanity the whole way. But, since I am not, I am open to pushing things a bit.......I just dont know what sense to make of those calculators. I dont want to give away any more bottom end than I have to, and I would rather use my shaved heads than go through another 5 hour ordeal under the hood of a boneyard Explorer. Plus they got my rookie bowl blend job that needs to be tested for the full junk experience.
I ran that cam in a flat top piston 5.0 along with the Trick Flow heads. Surprising how strong it was. The heads & cam are now waiting for action in the T-Bird 331. I will say, you'll need at least a 2400 rpm stall converter(will still buck a little) & 3000-3200 would be better. Also a 3.50 gear is a minimum. I'm gonna use this one in my 347. https://www.summitracing.com/parts/cca-35-349-8/
Most that want to run an XE cam in a 347 go with the XE274HR. It's proven to be one of the best off the shelf cams in a 347. The XE264 is really small for a 347 with it's short duration and spread lobes (114 degrees). With it's long stroke and bigger displacement you have to think of a 347 more as a 351 than a 302. Been all through that with a couple 347's in different configurations.
I really appreciate the input as experience in this stuff is vital to not wasting resources. That XE cam might suit what I am doing a little better than the trick flow. I have a stock stall and 3.25 rear with 25" tires. I read several threads about high compression (what I think is high) in iron head 302s, and some folks claim to run as high as 11:1. I need to go back and pair what they are saying with their cam choices. I think there are cams that would love 10:1 and pump gas, but I want to get as wide a torque curve as I can and still use my 9.95:1 junk, lol. So, you can bet I will be dithering over this a relatively long time before I pull the trigger....mostly due to a lack of experience. I have driven my car enough to know that sticking my foot in it is always part of the recipe. BTW, what compression ratio are you guys using?
I run a Trick Flow stage II cam which is similar to the Crane XE274HR in my 302 with 10.1:1 SCR. It is a fine cam but I suggest a 3500 stall convertor like my Summit Racing SUM-700370. I also run a 3:80 gear like Krazy Comet suggests. If you are not willing to run the larger convertor and bigger gear don't do the big cam. Otherwise, you will be disappointed in both drivability and performance.
Comp Cams recommend setup with the XE274 is 2500 stall converter and 3:55 - 3:73 rear gears. No experience with that myself as I've always had a manual transmission and 3.90 gears.
Don't get hung up on compression, with 64cc heads I doubt my Trick Flow cammed 5.0 was more than 9.5. As I stated, was a beast in a 3700 lb T-Bird.
I did say XE up there....lol....I was thinking the XE264, or maybe XE258. Being in a car 850 lbs lighter should reduce the possibility of detonation.....did you run 87 or 91 octane in it?
Here on East coast we have 93 octane, but truthfully it had slightly better throttle response on 91-ish. Used to mix the 93 & 89, would switch each time I gassed up.
I am probably beating myself to death with this cam choice thing, but I am getting close (I think). The TFS-1 is out after playing a dozen "sound" clips, and guessing most of the glowing reviews are based on people who really want to go faster than their HO cam. I dont want my car to idle like what I am seeing.....even if they are trying to sound cool at 700 lopey rpms. But, even the xe264 comes in more than one flavor, and some specs using 1.7 rockers? Would this do anything more than give higher lift and quicker opening speeds? The 1.7 lift specs have a more narrow LSA and a little more overlap, also installed at 108 ICL instead of 110, but same duration. 2 different part #s. Also, all these cams seem to be for computer controlled FI. Is there something to be gained from getting a custom cam that is designed for a carburetor? An extra 75 bucks seems like a small price to pay if a custom grind is better......I just need to do some more homework. And I read about 1000 threads where engines were built north of 10:1 using iron heads and pump gas. So I am going to be glad for my .020 out of the hole, junkyard, non HO pistons. I also quit fretting over the cc discrepancies of the valve reliefs after watching a 25 minute clip about a guy balancing an engine. Rods and piston assemblies had a one gram difference and were considered within spec. .4 cc of aluminum weighs one gram. It is amazing how much useful trivia one can ingest when the "want to know" is present.
