I took the block, crank, and head in. At the moment she's scheduled for a port, polish, crank grind, milling the deck and head, and oversized valves.

A few questions...
To get 10.5:1ish compression, how much needs to come off the block and head? The bores are not oversized. I am looking to run Premium pump gas.

Is the 1.7 and 1.44 valve combo the largest I can fit without notching the bores?

If I opt for the ford 300 valves 1.78/1.5, how much more work would be involved? Just bore notching?

Feel free to post anything else you'd recommend I do while it's at the shop.

Cheers!
RustyD

There's lots here that should've been done before it went to the shop...

To make the best use of the O/S valves you'll need to go for an overbore, and mock up the head on the empty block so you can see if the bore is in line with the chamber...Ford valves require good bore alignment, possible bore notching if you are under .060/.080, and chamber relief notching as well.

Your machinist will now have to determine how much to take off the deck and head to get your SCR, when disassembling the engine while the shortblock was together, running a piston up to TDC and measuring would have given you a "ball park to shoot for"...now your machinist will probably have to deck it .090, then make up for the rest out of the head (hope he can CC the head and knows that for every 1cc/,0066 has to come off the head...once he's under 44-42cc it goes quicker and the head won't have much meat to be used again if it has an issue), while in there you might as well plunk for new hardened exhaust seats.

If this is being street driven I would not worry about the polish...if you are building for race...get the short block done at the machine shop and send your head to Mike Jeffries, the sad and the bad is most machine shops won't know how to port the head (and by the time they flow test it on the bench and do more work you'll be out the $1000 anyway, and hope the guy doesn't over do it and get into the water jacket).

You can easily design a 10:1 slant six to run on regular fuel if you pick your cam correctly (also the build has to match the car's components, if you have a 2.76 rear and a stock automatic, those need to change to keep a 10:1 4 barrel engine "happy"). once that is all set, a distributor recurve becomes a high priority (along with EI).

I take it you've dropped the turbo build previously posted and are going with naturally aspirated instead?

-D.Idiot

Thanks for the reply. The turbo build is still in the works as well, I want something together for this spring to drive though. The motor at the shop right now was originally dropped off to do a stock rebuild, but I figure I should pep it up while it's in there. I know it's a bit of a late decision!!!

What overbore do you recommend for the 1.70 and 1.44 valves?

I go 40 or 60 over and adjust the chamber to unshroud the valve on my 1.7/1.44 Enginebldr/SI valve heads...what cam are you using? Before all this goes into the works if you don't have a cam in mind you will have other issues that need to be worked out now or wait a few months until it can be reassembled (you will be needing custom push rods at 10:1, and current over the counter cams won't support the 10:1, so a regrind may be your buddy at this point). Time for you to start shopping for the cam and use a DCR calculator to get one that will work for the build and drivetrain.

10:1 is a little more serious build (you will need to consider your head gasket options as well), a 9:1 is a 'pep it up'...

Time for you to do a search and look for what you want to do, otherwise you may end up like other members who let the machinist do the work and you end up with the bill and an engine that doesn't work out.

FYI

-D.Idiot

FYI- I had a head rebuilt years ago and had Ford 300 valves installed. The valves are the absolute maximum diameter you can fit in the combustion chamber, and I am afraid that there may be shrouding going on due to how close the valves are to the sides of the chamber. I have only ever used this head on an engine with a .060 overbore, and I don't think I would run it on any smaller of a bore. Frankly, I wouldn't use Ford 300 valves again as it required machining of the valve stems and the head to get the valves to be the right height and seat properly to work with the valve train.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

Not to hijack the thread, but I've seen several instances where you've said you routinely have .090 taken off the head. Is this pretty much a standard cut when decking the block due to the pistons generally being way down in the hole?

For example I'm getting ready to send a 65 block to the machine shop. Prior to disassembly I measured each piston at TDC and each was just about .170 to .175 or so in the hole. I'm planning on having the machinist take your .090 off the deck, using a Fel Pro head gasket and making up the difference on a never been cut stock head to get to about 9 to 9.5 to 1 compression. Cam selection (a regrind from Oregon) yet to be decided. Sound about right?

_________________
65 Dart station wagon slant 6 - now under construction
47 Dodge Custom 4 Door sedan
87 D100 Short Bed slant 6

Retired USAF 1966-1986
Retired US Postal Service 2004-2014

Yes, but you need to measure everything first.
It is best to deck the block first and leave the head thicker.
Not the other way around!
Depending on compression ratio and cam used, some guys have gone close to zero deck height to get the results they wanted.

_________________
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

Definitely....much like algebra, you're solving for an unknown quantity (deck head or both in volume will get me the X amount of static compression I want)...typically when I tear down an engine I'll measure the deck height to see what will need to go if I'm going to do a 'certain' build...it's best to take the bigger cut off the block first, and do an "adjustment" on the head for a few CC's...IF you cut the head...assemble the shortblock, then have to disassemble the block and take the block back to cut another .030-.050 off the deck to get your target it kind of gets labor intensive...(per hour at the machine shop could be spent on other fun things...)

Given that a stock 225 block going in is anywhere from .145 (late blocks), to .175 (some 60's and early 70's blocks or more), if you are shooting for a lower compression ratio on a guess .090 is a good start (as it leaves you with a deck height of .055 to .85)..depending on the head and intent, this allows access to a 9:1 engine (on a BL head that's almost a .010-.020 cut at a 54cc starting measurement on an uncut stock head)...or you can go from there if making something with a bit more "bite" (10 cc cut or .070 will put that build in the 10:1 range...or if you went all out and took a .125 cut off the block and another .090-.125 out of the head and went for 12:1...the motor destined to be in my car next has had the block decked for a .045 deck height- a .130 cut, and the head took a .100 cut...target was 12.35:1)

The point to really drive home (beating Ted's dead horse here), is taking the measurements first and doing the math is the key to getting what you want and allowing the regulars on the board to check your math so you get what you are planning)...

The other part of the equation is the head...if you take everything out of the head instead of the deck, and the head warps, or you cut into the jacket while porting, etc...you will be out the machine work on the head and will not be able to just "get by" if you have to install a stock head in an emergency (or keep down the machining costs if the replacement only needs .020 off and the OS valves installed...really sucks to have a set of $150 valves, and $500 in seats and machine work end up being another $50 head, and $500 in machine work)...

You can use one of the on line calculators to put in your stock block numbers (and chamber volume if you can measure), to see what it was stock (I've seen 7:1 in a 1963 truck motor up to 8.2:1 in a stock 1976 block)...then if not so much the math guy, you can "play with the numbers" and see what needs to change to get 9:1 or 10:1....(a little off the deck and I need to have a head with x CC's), so at least you can give the machinist the target if he's going to be doing the measuring as he completes your parts....

Exception to the rule...if you are doing the whole enchilada...you will plug your final numbers above into a DCR calculator and input your chosen cam numbers...this will ultimately tell you if you will be using pump gas, race gas, diesel, or smokin crack... (so going 10:1 and installing a comp cam 252 is not going to happen...numbers on the desktop dyno look awesome...DCR will tell you it's going to ping on any type of fuel...likewise someone that goes 9:1 and installs a 290 duration cam will see that the cam bleeds down the compression so bad even a turbo won't help...)...Doc's golden number of around 8:1 DCR for a street engine has worked out everytime for me (even on a 10:1 engine...with a distributor recurve it will run lower grade pump gas and save you $$$ if daily driving on a budget but want some fun.)

2 cents,

-D.idiot

so youre saying, if you didnt measure anything (im an idiot) before disassembly, and you have a stock and uncut 1970 225 5 freeze plug block you should deck it 90? the block had to be bored .40 using flattops
the head is also uncut, from 1970, shave 20 off it?
and that should get me in the 9:1 ballpark im looking for?

using stock valves, and 340 springs

also, will this work well with a 264 .440 110 cam,a 350cfm holly two barrel stock ex. manifold and 2.5 all the way out?

its 65 valiant 3spd manual stock 7.25 rear

im also doing the h.e.i conversion with dizzy #3874714, the curve of that dizzy should be good as stock correct?

do you have any idea what h.p. and torque numbers this build should yeild? also @ what rpms? around what rpms would an engine like this redline?

thanks!

A this point I'm planning on a regrind cam. I'm dead set on a 10:1 motor. Fuel economy is of absolutely zero concern. This thing will be a Sunday afternoon hot rod that rarely sees only part throttle. It can get 5mpg for all I care.

So on a stock uncut 69 block you are saying that a .090 cut off the deck and .070 cut off the head will get me to 10:1 roughly? The felpro gasket I'm using is roughly .030 thicker than stock gasket. Should I take another .030 off the deck to compensate? How would I compensate for a .040 overbore as well?

I do not trust this machine shops judgement, so I want to tell them what to do. Not let them decide. I have until Monday to decide what to do.

If you didn't measure it before, we can throw darts at it all day....090 is to get it close to start, then you'll have to assemble the short block (put the crank and one piston in at least) and measure the actual deck height...then adjust the cut on the head based on what comes out (it will be tough to say what the head is going to be like, and how sunk the non-hardened valve seats are...

I do not like the Comp 264, it likes thing higher on the rpm and leaves less torque in the low-end range...the 252 has better manners on the street and launching the car from a stop...if you can get your actual numbers run through a calculator and firm it up to come out at 9:1 (better to be a smidge over 9.1-9.3:1 in case something is "light"), it will run similar to the original engine I built for my duster, it will probably weigh in around 150-160hp and a gain of 10-20 ft lbs of torque in the useable range... 65 with a 3spd manual and the stock 3.23 ratio will have lots of fun without destroying the clutch. Given Comp's cam core reliability lately, I'd opt to have a regrind based on Ted's cam as the better option, but do not exceed 9.5:1 compression ratio.

dizzy #3874714, the curve of that dizzy should be good as stock to start with, being that you are improving the engine and the car is lighter than the car that originally came in, you will most likely pull the long looped spring and put in a medium full coil spring and get a bit more out of the package....


2 more cents...

-D.Idiot

Food for thought:

Get on an online compression ratio calculator and use these values to dial it in:

1969-70 deck height is going to be closer to .175 (.090 will put it at .085-ish)
1969-70 head if in good shape may be about 56 cc
Fel-pro head gasket will be a 3.5" bore and a .039-.043 crush height (pick the .043 so you know how 'low' it could be on SCR).
3.44 bore, 4.125 stroke, 0 piston dome...and you are off and running:

http://www.gtsparkplugs.com/CompRatioCalc.html

As above...
input your values...

.175-ish deck height minus .090 is about .085
Felpro comp gaskets are a .039-.043 crush
.070 cut off the 56cc stock head (assume no change due to new seats and O/S valves...which your machinist will have to install then measure after he has done the job, to determine the cut...but at .0066 per 1 cc we are taking about 10 cc's out of the chamber...
Yes you will a have to adjust your calcs to compensate for the overbore...

After plugging the above numbers in, the .090 cut on the deck (assuming that you had the .175 to begin with and not .170 or .165)... and the .070 cut on a stock head (or a combination of valve changes and milling done to make the chamber sizes final out at 46 cc) will put you at 10.56:1 SCR...per the calculator above...but there are a lot of assumptions here that need to be solidified before moving on...(you could even have a .100 cut taken off and less of a cut on the head....)

Time for you to check with the machinist and make sure what you had and how much really needs to be taken out.

-D.Idiot