1970 dooe 351 w heads 2.02 int/ 1.60 exh.3 angle gasket matched ports .they are a fresh rebuild. what do you think they would be worth and how much difference would it make on my 302 in my comet. thanks
The 70 heads will raise compression slightly (.3-.5) and the larger ports and valve will add a lot of potential. By themselves you will be limited by your cam, intake and exhaust system. With a 570 to 600 cfm carb, a Performer RPM intake and a good set of long tube headers with a free flowing exhaust you could expect somewhere between 325 and 350 hp. Compared to a stock 210hp 302 you are looking at 16% increase in power and torque. If you change to 3.55 or 3.75 gearing, a 2500 -3000 rpm stall converter you could expect nearly twice the torque on take off with nearly the same top speed. (considering that you have a stock converter and stock gearing. The addition of a big auxillary cooler for the tranny and a TransGo 40-2 shift kit you won't believe it is the same car.
right now i have a 302 w/ edelbrock intake and (650?) holley 4 brl, 3.55 gears and a 2500-2900 stall converter. so i can excpect a big change with these heads??????????
If your comet has its original 302 block in it, the deck height is taller than pre 73 blocks at8.229"(unless you decked it).This combined with the D00E heads "nominal" 60.4 cc chamber volume and the 302 dished pistons will only yeild a compression ratio of 7.8:1 Add to that a 0.040 head gasket thickness and you are even lower on the compression ratioYour 302s' stock compression is 8.0:1.So unless you are useing a fat cam with a late intake closing point to fill the cylenders.I cant see it making over 300 horse.At least not down low in the rpm band.It will breathe like an olympic runner though.(It will come to life above 3 grand)If you have changed the pistons to flat tops and or are useing the shorter 8.206" deck block then you will have much better compression (around 9.3:1) 9.5to9.7:1 with flat top pistons.These few incidentals along with Pauls recommendations about headers/converter and so on,Can put you over the 350 horse hump.Cam selection is going to be very important to making that kind of power as Paul stated.If you want to get the power with the 351 heads on a tall deck block.Mill em to decrease the chamber size for starters.They are good heads dont get me wrong!!Its just that taller decks and stock dished pistons hurt compression with those chambers.fords specs on chamber volumes for stock heads are dubius at best.(they tend to vary by as much as 7cc in either direction)Not trying to burst your bubble just thought you should know some of the pitfalls regarding head selection for our favorite little smallblocks.Hope this helps you,Also,202 intake valves dont work with the stock pistons valve reliefs.You will need to get different pistons or have yours cut for the bigger valves.This is especially important when running a cam with lots of lift.Good luck.
mavman is absolutely correct about the valve relief. they are cut for the 1.94 valves. Had to flycut pistons in the block to over come this. I had not run eng yet. those are good heads. I normally cut mine .060 to get down into the 50s cc range.
The best 351W heads are the C9OZ-6049-F heads with 57 - 58 cc chambers. The D0OZ-6049-C heads had slightly larger 59 - 60 cc chambers These two heads had the larger 1.84" intake valves and 1.54" exhaust valves. The '73 302 heads have 62 - 63 cc chambers and the smaller valves. The '73 - '76 302s start with 8.0 compression so the smaller chamber gives the engine 8.3:1 compression and if it is milled .050" the compression jumps to 9-9.3:1 with stock iron heads from Ford. Add in larger valves and good job of blending the pockets and ports and you have heads that are extremely good at delivering A/F to a 302.
PaulS ,where have you found that the 69 head has a smaller comb chamber? I have measured several un cut heads and they are nearly the same as the 70 heads.There will always be a small variance because this is not a machined combustion area. Yrs ago there used to be the myth about 4bbl 69 heads. thats what it was/is, a myth. Yes the 69 was the only performance 351W in that era, but the 69 block is .023 shorter that is why the compression is more.I could possibly be wrong about this.
Rumor was 4-V 351 heads had 58.2 CC chambers like the 69-72 302s'i have a set of these heads and the chambers range from 58.7 to 61 CC between all 8 chambers on both heads.Manufactureing tolerances were an oxymoron to say the least with ford heads.Yes the decks were shorter on the 69/70 blocks at(9.480) compared to the 71 and up 9.503 decks on 351 Ws' Hence the greater compression on the older blocks.
Well I looked it up in the Ford cylinger head exchange books that I have and the figures are correct for THAT part number. There were more than one head in use at any one time. The C9OZ-6049-F was used in 69 and 70 on some engines and the D0OZ-6049-C heads were used from 69 to 72. (I know it doesn't make sense that a head dated 1970 by its part number would be used in the prior year but according to the records and books it was used in the last half of 69 on SOME engines. With Ford you never really know what you have unless you can get the build (sheets) numbers on each piece of equipment in your car.
The Ford head inconsistencies boggle the mind!!!great job guys on clearing em up.Geardriven is now well informed and can make a good decision now as to the potential with those heads of his.Man I love this place!!! PS: Paul,you rock!!
my running C9 heads , 58cc, had them professially ported , have flow numbers around here somewhere, if i find it ill post em up, also had the air gap ported to match...the guy who did this work said 390-400hp FWHP shouldnt be hard...alot of old school guys said 69 351w heads are the best of the best far as stock fomoco casting
I only have one comment: Double check those valve measurements. Someone correct me if I am wrong, but 2.02"s don't fit stock head castings. Especially with 1.60" exhaust valves. This is why aftermarket heads have the valves spaced further apart. Always have from what I understand. I had 1.94"/1.60" heads and the valves could barely fit a sheet of paper between them. Stock for that head is 1.84" intake. 1.94" will fit. Make sure the seller isn't pulling the wool over your eyes. Good luck Dave I will make another comment: Those heads are awesome with the exhaust port ground out.
Not according to all the flow numbers Ive seen. The early gt40 heads beat em out marginally, and the later gt40P heads are even better. Not to mention the late model heads already have hardened valve seats and are WAY easier and cheaper to find. The only drawback is that they have larger chambers, and the later heads have relocated spark plug angles, which depending on what car theyre going in, isnt always a big deal. Given that you already have the 351 heads, I say go for it! Theyll still work pretty well, but 400 fwhp might be a little high. Id say 350- 375 tops, which is still a night and day difference from what you have.
Dave, A good machinist can install larger OD guides at an angle that will move the head of the valve the .080" necessary to install the 2.02" valves. Then cut the existing seat out and install an insert in-line with the new guide. The angle is so small that unless you look close you can't tell its been done. The rocker still aligns with the tip of the valve so the geometry is vitually unchanged. The ball pivot will allow the rocker to stay on the valve. If you run roller rockers you have to angle drill the hole for the stud too. That is what had to be done with my 350HP 289 that I built in the early 70's.
Sounds plausable... never seen it myself. Stock for stock, the GT40s got it all over the 351s. However, when the 351s are max ported, they really cook! Well ported C9/D0s outflow several aftermarket heads. 69 heads only differ from 70s by 2cc in chamber size. Not big enough to worry with. D0s were used into 73, and got hardened seats somewhere in there. These heads still had all the goodies until half way into the 76 model year. In 74 they got some emissions plumbing, so many folks don't look at these heads the same as C9s or D0s, but other than the AIR plumbing, they still had the big valves/small chambers/big ports. Mid-76, they became junk.
