I have the 302 in my car, and I am planning the rebuild process for my engine. Does anyone know whether or not the port and polishing of the cylinder heads will do any good? I would like to mill my heads down slightly to gain a 9.0:1 ratio , and I want to get the heads machined to accept conventional rocker arms. Does anyone know about how much cost I would be looking at if I did all that along with the port and polish job?
There are some things you need to know about this head project. Milling to go a full point in compression will require quite a bit to be taken off. Next there will be a problem getting the intake manifold bolts started on re assembly because the heads will now set closer togather on the block. On porting, you can go all out on pocket porting and exhaust port clean up but the results won't match the effort put forth in my opinion. If your motor's pistons don't come to the top of the block deck, getting a raise in compression will be difficult with out replacing them with a new set that comes to the top of the deck. I went all through this with 73 heads/block, full porting, pistons, screwin rocker studs, guide plates, roller rockers and special push rod length, block milling etc. Today I would have gone after market alum. heads and been a lot of performance and work ahead.
Interesting subject, Just swapped the heads on the '74, and I must say, porting and polishing is WELL worth the effort! You will, however, have to have a good knowledge of where to grind and where not to grind, that is if you do it yourself. If you were to hire someone to do it, it normally costs between $500-$2000 depending on how far you want to go. Dont get me wrong, it does make a difference, but the rest of the engine must be changed to take full advantage of it. Personally, I'd buy aftermarket heads.....cheaper in the long run, and will generally outperform ALL ported factory heads. Here's a good guide to porting if you want to tackle it yourself: http://www.fordmuscle.com/archives/2000/07/homeporting/index.shtml Be forwarned....I spent over 75 hours total on mine!
My current compression ratio is 8.4:1. I need to reduce my combustion chambers about 3.3 cc. Also remember in '77 they used the 351W heads and that is what ive got. My pistons are already high enough to compnesate for the bigger combustion chambers. Mine is around 67.5 to 70.5 cc as compared to 63.2cc which I believe were on the earlier maverick 302s.
Or, another option would be to find some earlier heads. Most earlier ones have 58cc chambers which would work great for your application. I used '75 351w heads, they have larger intake ports, but have 1/2" bolt holes (which was no problem because my block had 1/2" studs in it already).
Heads and such Just 2cents worth, I spent around 750.00 not including rockers or guide plates on an set of 58cc heads. 1.94 and 1.60 valves installed etc. They worked well on our drag Mav but always limited the power range to around 5800rpm, finally got a win of 1000.00 and put another 250.00 with it to get some Performer RPM heads from Edelbrock. I would definately go that route, picked up 4 tenths right out of the box and with no porting done. Weight reduction is another plus. I need a little clarification on your statement that in 77 Ford used 351W heads on 302's or did you mean that you have put a set on your engine etc. Just have never seen them stock from the factory with the 1/2 bolts in the block. Anyway if you are industrious then go the port and polish route on yours, while there off let us know what the piston to deck height measures and then somebody here can give you an exact compression ratio.
Thanks for all the help and advice. All of it will be useful when trying to consider which route to go. Right now I have the stock '77 heads on my 302. I have a Ford Performance book which says that in '77 ford began using the same cylinder head for the 351W and the 302. I just recently check my shop manual (1977 Car shop manual for fords) and it shows the same combustion chamber volume range for both the 302 and 351W engines which is 67.5 to 70.5 cc . I am assuming that this information is right, but it might not be. Knowing this information, I just figured it would be better to mill the head down only slightly. I also checked on my pistons. I used napa's web site to compare my pistons to the pre '77 mavericks. Here is the difference. '76 replacement piston for the 302 '77 replacement piston
David, you are correct in saying that ford started using the 302 head on the 351. Valve sizes and the such are the same. I agree with everyone above, the problem is it is expensive. I haven't really tried selling these yet, but I have a set of 68' heads with the 58cc chambers. They have 3/8 screw-in studs with guide plates, dual valve springs, 1.94 IN and 1.5 EX, the exhaust thermactor hump has been removed and the head bolt holes have been drilled so they can be used on a 302 or a 351. They were used for one race season. Going from a 68cc head to a 58cc head would give you a good full point in compression. What cam, intake, carb and exhaust are you running? These heads will NOT flow like a set of aluminum heads but they may be just right for a street driven 0-5500rpm motor. I would just clean them up, paint them and slap 'em on. I'm firm on the price of 325.00. If you are interested email me at wm12345@hotmail.com. I'm almost hesitant to sell them as I can't replace them for that price, but I'm trying to raise funds for a set of 351C heads. I think you will find that the cost of machine work and the like would be well above what I'm asking for the heads. To my knowledge they are in good shape, but as with anything used there is a risk. If you were to find anything seriously wrong with them I wold be willing to work something out. If you would like to see my ebay feedback look-up nightlight1. Also, I've been on this board for several years now and have dealt with several including K. Merring. I'm also an IMCC member. I can drag them out and try to get some digital pics as well. I offered them to somebody else on the board several months ago. Can't remember who that was, at any rate, good luck with whatever you decide to do.
david, just something a little different on the subject of heads. Air flow is the thing you are after, that raises power as well as improvement in compression no mater what head configuration is used. We here, will be building a 351 windsor for short track sprint car racing, useing nearly all Ford parts. The heads are the N351 motoersports, single plane intake and 800 cfm carb on alky fuel. The combo makes well over 500 hp with torque in the 475 range. The peak rpm is still only in the 6500 area with a very broad torque band starting at 2000 and peaking around 4500. So the dream of high power for street use is very real but the heads have to flow enough air to support the power level as well as the camshaft has to compliment that ability.
david, the reason the book says you have the same heads as a 351 is because Ford got rid of the 351w cast head as it was in 69 and 70. Basically, 351 windsors had 302 heads, not the other way around. All else working together, each point of compression is worth about 4% more horsepower. Not as big a jump as you would think. Flow is far more important. The machine work you are considering may cost you over $750, which would be far better spent of aftermarket heads. I have a 77 302 as well and I found a pair of 1970 302 castings with screw-in studs installed, hardened seats and a fresh valve job. The price was damn cheap, so I am going that route. If I didn't have a column shift and could install headers, I would have gone aftermarket. Since I am stuck with manifolds these heads will be good enough. Either get an older set of heads set-up, as listed above, or go aftermarket.
The cam I am planning on using is the same as the edelbrock 2122. I was going to try to use the replacement cam for the 84 GT but as in earlier posts I decided to go ahead with the the more aggressive cam. The intake will be an edelbrock 3721, which supports the egr system. I got the egr spacer and carb (which is a 4180C holley) from an 84 GT. I also have the column shift and could not easily fit headers on my 302 so I did not get them put in when I got my dual exhaust. The exhaust has the h pipe crossover section and is 2" pipe with turbo mufflers and of course the catalytic converters. I dont know if this info helps anyone. I know air flow is a big thing in getting HP but I also have to conform to emission laws. I am taking a chance with the cam, but I figured that the higher compression would not be much of a problem. However, I am not sure if it is a good idea to get bigger valves. I guess I under estimated the cost of getting my heads improved while keeping the same size of valves. I guess my next question is whether or not I can atleast get a decent amount of HP with my heads as they are if I install all the above parts in the engine?
302 Mods I think you will notice a nice increase in overall performance, but the potential HP increase will be restricted by the manifolds and such. The emission laws are not best suited to performance stuff like we would like. Don't be discouraged though, if you want a bit more seat of the pants performance may I suggest a deeper gear such as 3.55 or the like. Also if you are so inclined, you could up the stall on the convertor, like the TCI street fighter model. Just call them and give your engine and gear specs and they will recommend what stall to use. Those boys at the emission office will never know.
If you're stuck using stock exhaust manifolds, aftermarket heads wont help much. I am going to use a Comp Cams Extreme Energy cam, as they have a profile that boosts cylinder pressure, which is like boosting compression ratio. I got a grind that wouldn't be too much for the manifolds. EFIMav heads above sound like they might be perfect. If I didn't already have heads, I would buy them.
maxpower maxpower, I think you are correct. The heads are perfect for a car without headers and a smaller cam. The valves are not that much bigger and removing the smog "hump" would help any engine. They are the small chamber heads (58cc). If anyone is interested let me know. I'll list them in the parts for sale section. Max power, if you are interested I can meet you in Rochester MN. I'm an hour away from there, would be able to eliminate shipping. David, also, don't forget you may need new springs with the cam.
