My current engine is a fresh 302 bored .030, basically stock short block with flattop pistons, and a crossdrilled crank. On top is a set of World Products windsor Jrs, and they work OK, but I think 180cc may be a bit big for a 306 with a flat tappet equivalent of an E cam (222*@.050, .498"). The big kicker is the revised spark plug angle like the gt40P heads. I was constantly burning plug wires, even after denting the headers. Anyway, money is in kind of short supply, but I want to get the car back together after doing some other things to it, and Id like to make 400hp when its all done. I know I can just get a set of AFR 165s and be done, but at $1400 a set, I think I can do just as good for less. A set of used gt40 heads can be had for $200 or so, and I have connections that can port them for a reasonable price. My thinking is if I spend $200 on heads, $800 on porting and other parts, Ill still be ahead by $400 leaving room for a retrofit roller cam and lifters. Im already set on new headers that only work with the old style spark plug angle, which kind of rules out using the existing heads. Am I on the wrong track here, or will this work? Opinions? Suggestions?
afrs are where its at but i think your fine with the heads you have why not step up the cam to a z cam or another manufacter , more cam lift and duration will utilize the heads more
You're wanting to spend $1000 on some iron heads? You can find good used aluminums for that price and be farther ahead. $100 more you can buy new Edelbrocks. And for any type of performance application you really don't want to run a small base circle retrofit cam, they've been shown to twist and bend with higher rpms and spring rates. Get a full size roller cam and use the Crane link bar lifters. Personally I'm not a fan of Ford's "alphabet" cams.
the engine in my mav seems pretty simular to what your talking about. its a '91 with forged internals, e-303 cam, mildly worked iron GT40's, headers. all the usuall stuff. compression should be in the mid 10's i believe. the builder said it should be worth power in the low to mid 300 hp range when it was EFI'd. im running a T289 and 650 demon though the motor took a stock 91 fox body AOD for a 13.4 sec pass
GO AFR or stay with what you have, and switch to an x303 ford racing cam.. listen to mine..306 x303cam gt40 heads that motor was going in my mav.. but selling the mav so.... Desktop dyno says 410 horse at the crank........
My 331 with the Z303 sounds exactly the same. Great cams. Seems to me though your tach is off by about 2-300 rpms. Showed it idling at 1000-1100, sounded more like 6-700.
Nope checked out with a buddies stang and his read the same in my car.. Its idling at 1050 also check it with my nifty tach gun.. And yes those Zand X cams are sweet sounding....
I see a lot of...desktop dyno #s...seat-of-the-pants #s...does anyone have any ...real dyno #s on these heads? if these are true...400 HP heads...how could they sell...AFRs... ILM: AOD,RDB,RSP,AC,CTB,DDG,AR,TEF,MSDD,H600,RFWK,SFCs, 6A,AFRs,MS...
"but I think 180cc may be a bit big for a 306 with a flat tappet" quote from OP...who ever told you that ????? thats old myth... a custom tight lash solid roller cam and modern aluminum cylinder heads(180cc or bigger)and associated valve train is the way to go... learn from the elders and build it the rightway the first time and you will save a lot of money in the long run... if it is not with in your budget, sell what you have and save for the good stuff... it is just common to fall prey to all the magazine hoopla,web hear say and those dyno comparisons,I know I have... NOW if it is a mild budget engine build, use the gt40's,a ford letter cam,VS carb. and what ever power you make is what you make... it takes many years of trail and error and cash to make reliable horse power...BTW my junk runs two times a week with e-303,6901,600vs,rpm manifold on a 14.10 dial... at the track and no break downs...daily driver...that equates to 250 hp 300tq...good luck!!!
You are correct about the heads and what they will and wont do.. The flow numbers for the GT40 heads are okay, just OKAY. Thats why I recommended to use what he had or spend the money on the good stuff.. The heads (gt40s) I had on my coupe had many port and polish hours by a good friend of a friend.. He ran the heads on his car for about 6 passes at the track and 2 long days of dyno pulls for fine tuning and they didnt give him what he wanted, thats how I got them. Cheap and race ready... But in my opinion they are not worth buying and putting more money into, you only see a small return..Thats me, thats what I know, hope this helps someone..
Here are some flow numbers from the Ultimate head shootout in the MM&FF magazine from a while back. http://airflowresearch.com/articles/ultimate/Group1/Part1/A-P1.htm http://airflowresearch.com/articles/ultimate/Group1/Part2/A-P1.htm e7te.............122/84 gt40p............136/97 gt40 ............137/108....<~ the old aluminum "Y" head? windsor jrs ....138/106 holley 17*......156/111 canfield.........156/115 edelbrock.......154/118 brodix............156/117 afr165 ..........158/135 So it would appear that the old windsor jrs I have kinda suck, seeing as how there are smaller heads that outflow them at all lifts. Big port + low flow = poor all around performance, which seems to be the case as the Wjrs only beat out the stock gt40 heads by 15 horsepower. Not to say they couldnt be ported to exceed a comparably ported gt40, but then Im still stuck with the spark plug angle that wont clear my headers. The other thing I think many of you may have missed is that I dont have a roller block, its a 70something (hey, I got it for free and built it years ago when I was still wet behind the ears at 17). Its a flat tappet cam that specs the same as an E cam. Now that I put it all out there, maybe I will just get a set of used aluminum heads. Either way Ill be selling the ones I have. My only real concern is how do I know which heads have what spark plug angle? If I buy a set and I cant use em, Im gonna be PISSED!
I have AFR 165's and running Hooker 6901's with no clearance issues. Bought the AFR's when I test fit the Hooker's and saw the spark plug clearance issues on a set of Windsor jr's I have. I don't think you will run into issues with the Edelbrock heas as well. I am sure someone will chime in on that.
I use jr's on my car and i had to fight the header deal for awhile till i figured it out. Now i think its been several years since i burned up a wire. I think i would have some port work on the jr's before i would buy gt40's. What valvetrain configuration do you have on the jr's what are the gt40's?
I think MOST heads will work, I just dont want to find out the hard way a set I buy wont work. On a different note, I may have found a set of headers from FPA to clear the P style heads. Ill call them tomorrow and find out for sure. Valvetrain configuration on the Wjrs is whatever they came with stock, good to .550 lift I think, with Crane 1.6 rollers on 3/8 studs. I also recall seeing somewhere that the retainers or valvesprings or combination was pretty heavy and not that great for high rpm.
One other thing i would advise against the use of any alphabet cams. Their is way better stuff out there.
