As some of you know I am building an 82 hydro slant using Clifford 264 cam and intake with dual carbs. It was recommended to mill the head .100 and the head .020 giving something close to 10.5-1 compression...their words. Talking to Pacific Engine and Machine in Tacoma they were concerned about being able to run pump gas (best I have seen is 91 octane here) is this to much compression for what I can get for gas causing pinging ad detonation? Would it be better to take more off the block coming close to zero deck then take the rest off the head for better quench?

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AlaskanMopar
1970 D200
4wheel disc Conversion
Skyjacker 2" Lift

I recommend Bud's Machine out in Lakewood, right off the Bridgeport exit on I-5 south. Bud has rebuilt numerous engines and heads for me over the years and his work is top notch.

To figure out how much compression is "too much" you (or the machinist) is/are are going to have to spend the time, take the measurements, and do the math to figure out what the dynamic compression ratio of the engine will be.

Perhaps someone more experienced with aftermarket parts will be able to give you a ballpark estimate of what the compression will be will that much milled of the head and using that cam. It will help if you can tell us the diameter of the pistons, how far down the pistons sit in the bore at TDC, the average volume of the combustion chambers in the head you are using, and what centerline you are going to install the camshaft at.

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Casually looking for a Clifford hyperpak intake for cheap.

That cam and that compression is not going to be 87 friendly

It may not be 91 friendly,

My 9.25 CR with Erson 280/270 (advertized duration) was OK on 87 ....in a light car with gears and 5 speed.

Same cam and 10:1 requires 91

the higher the compression ratio ,,,the more cam you need to keep cylinder pressure optimized for your fuel choice.

That 264 is a tiny cam....with big compression and a heavy truck.


On my fleet trucks I like a 262 duration cam with 8.5:1 CR. Pull big freight on regular fuel.

The answers to your questions are to be found in a dynamic compression ratio calculator. Skew the results to reflect heavy truck with big tires.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

You can actually run the 280/270 on about 10.2:1 compression as long as it's in a car, and you recurve the distributor and it will run fine on 87, but will perform better on 91-92...that being said a lot depends on the lobe separation and how much you advance the cam as well....

I plugged his desired static CR in my DCR calculator...the clifford cam is 264/264 110LSA 4 deg adv with a .444 lift at 1.5....(which sounds suspiciously like the Comp Cam 264...)

Assuming the following data:

Standard bore, stock rods, standard flat top pistons (if you have the late model low compression pistons with the dishes you will have to compensate). Combustion chamber at 52cc, cut the deck height to about .038...and he uses a Fel-pro comp gasket... bringing him to 10.5:1...
Cam set up to be centerlined at 4 deg. adv...(106)... put him at 8.81 DCR...so that is super and possibly some more...if he advances the cam to a 102 centerline he's up at the 9:1 DCR mark...

To put this into perspective...my drag only engines at 11-12:1 SCR...and a large cam were more tolerant with a 9.2:1 DCR, and with a good recurve they broke in fine on 92 octane, but when pushed for actual driving and drag racing (even using a 4.56 rear ratio which is very "kind" in getting anything rolling) they required 110 leaded or a "blend" of 100+ octane (a ratio of 92 and 110)...


Stuff to think about when designing your build...especially when you advance the cam to gain more low end torque to get your brick rolling...

Im bored .060...using flat top pistons. Block deck is shaved .020 for now. So what about staying with the hydraulic rocker assembly and push rods with the clifford cam and not taking .100 off the head...just take off enough to surface and maybe a bit more off the block. If I stay full hydrauilic like it should be anyway shouldnt that work?

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AlaskanMopar
1970 D200
4wheel disc Conversion
Skyjacker 2" Lift

Oh and the oversize valves wlll be used as well 1.70 1.44

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AlaskanMopar
1970 D200
4wheel disc Conversion
Skyjacker 2" Lift

Key points to consider when tuning.

1. What will this engine go into?
2. How much does the vehicle weigh?
3. Will you be hauling or towing?
4. What is the rear-end ratio?
5. Are willing to a distributor recurve?
6. Is mileage a consideration?

There is not that much overlap with that cam to bleed of the increased compression.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Yea I see what people are talking about now. There is no way this combination will work to Cliffords specs without causing major problems...just had to aquire enough info put the pieces together in my head. Going back to a hydraulic cam and push rods. talked with the machine shop and we are going to do .020 off head, .030 off the head, oversize valves and get custom pushrods if needed

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AlaskanMopar
1970 D200
4wheel disc Conversion
Skyjacker 2" Lift

If you regrind your cam, you can keep/use your stock push rods. Everything will zero out in most cases. The amount of regrind may match the .050 your taking off. That is what I did.....and you get a better running engine. Look at my cam specs below. Cost to regrind the cam a few years ago was only $35.00. I know it has probably gone up a little but will be less than a cost of another set of push rods and you will have a much more torque and better economy.

Click on the link below my name to view pictures.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I believe Oregon Cam was charging $75 for a regrind a year ago, when I ordered mine, as opposed to $150 for a new one. I still think that's reasonable though.

$75 regrind, $15 repair to fuel pump lobe, & then shipping. This was 2 weeks ago. Still a good deal and great people to work with!

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6