talk to them about what they can do for you and what it will cost you and just prioritize from there. Obviously you won;t be able to do it all up to the Nth degree when working on a budget.. but you can certainly make the most of the cash that you do end up spending here. 1.90/1.55 would work well. 4 angle jobs give decent bang for the buck.. with about 98% of the capability that a 5 angle would give you. Plus.. the factory SBF exhaust ports short side is so tight/squashed.. it's tough to get anything substantial out of a 5 angle job due to such thin cuts at each angle anyways. as for the seats that were already installed. it's doubtful that they were cut for huge 2.02 valves anyways.. and a 1.90/1.60 should still leave enough meat to end up with an excellent throat to seat ratio for good responsive flow on a smaller motor like this one. .87-.88 ratio would be my personal max/optimum for a smaller street engine like this. Anything higher than that will give up low/midrange flow in trade for high lift flow and hurt most milder street motors. Which roughly equates to a 1.7 throat diameter divided by a seat diameter of 1.9(actually closer to 1.89 when considering the slightly smaller seat diameter). In other words.. 1.90 valve should have no larger than a 1.7 inch throat about .200-.250 down from the seat. Look at the hand blending done to this sbc head to get an idea of really smooth radii and the smaller throat compared to the valve seat(tough to see but is all I could quickly dig up for now. It was roughed in with 6 angles..hand blended to remove all the angular transitions.. given a 3 angle touch up for final seat layout.. and then hand blended VERY carefully one last time to rid the transitions from the top and bottom cut. while you will never get that casting even remotely close to this one no matter how much cash you spend on it(sbf are too shallow and you'll knock the ass off the shortside before optimum is ever reached).. but it shows what a good design looks like and any emulation of these characteristics will pay off. Properly sized, machined, and engineered heads are what takes an engine from "good" to "great" and shouldn't be underestimated. I'd talk to your machine shop and see what they think of the heads port work and what they can give you for your money.
I have to agree that 1.90/1.60 is better and 1.84-1.85/1.54 would work well also. How large can you go with the pistons. unless they are cut out. 1.94 would be pushing it
Okay, talked to the machine shop. And they said that i should buy a cam shaft before doing anything else, so that i can optimize the heads for the cam shaft. They took some measurements for me, and the valves you guys mentioned will fit. Theyre going to do a 4-angle valve job (once i find out how long the valve stems need to be and order the valves) and i might have them grind the exhaust to 1.56, but they weren't entirely sure why i want them to do that so i need some good explanation there. They said that i need new rockers as well since the one i have are have rails, and won't work with the screw in studs and the set up i have. I was curious if these would work well? I'm going to call Cam Research tomorrow and have them grind me a camshaft. Once i get the cam shaft, can you guys help me read the cam sheet and decide which springs and valves should be chosen. You guys seem to have pretty good ideas..
When you call and talk with Cam Research ask them what springs to use with their specific cam...............they are the only people that will know for sure..........................and you will only know what length valves to order after you have put the cam in the motor, used someone's (Summit/Jegs) adjustable push rod, have the installed spring height figured out (by talking with Cam Research when they tell which spring to use and will have all of the specs, closed/open spring pressure, installed height, etc.) then you can use all of that information to determine what stem length you will need.......you can't guess at this. I can show you what rocker arms and push rods look like when they have the improper length push rod.................and coil bind or not enough lift can also happen with the wrong length push rod..........and this goes hand in hand with using a degree wheel and checking the cam specs to determine actual cam timing............................not just guessing and hoping it's right....................if I hadn't have done this with my current motor I wouldn't have found out the new billet cam was actually ground different than the specs said it was.............................and another reason I was able to pull almost 650HP out my outdated 408 with heads/head technology that is over 20 years old.
To reiterate once more.... You shouldn't be asking on here about what springs to get. You should ask the cam manufacturer and buy their springs that match the cam. They may very well have a couple different springs that will work with the cam depending on your installed height.
And I believe typical chevy valves are shorter than ford valves so you should keep that in mind because it can effect installed height (which will effect spring choice) and pushrod length.
Actually I believe SBC valves are slightly longer than the SBF... I have to use longer pushrods than stock with my Trick Flow heads because they have Chevy length valves...
Hmm, I thought they were shorter. I'm pretty sure the tips are shorter at least. Either way its something that needs to be taken into consideration.
first off.. a CUSTOM cam is optimised to the heads.. not the other way around. Cam research specializes in this stuff and all you need do is tell them what you've got.. and what you've done to it so far. They will determine what's best for the heads projected flow range and vehicles spec's/engine spec's/intended usage. Unless you're flow benching the heads first before spec'ing the cam.. the heads don't need to be done first as long as you know EXACTLY what the final configuration will be. They do enough cams for those motors that they'll easily know what those finished heads flow within 5-10 cfm. As for the valve lengths.. there's really no need to over complicate valvetrain choices here. If you peruse around the parts stores these days.. there really is no.. "this fits Ford.. and this fits Chevy" anymore. Especially with all the aftermarket castings and cam choices these days. The stem sizing pretty much makes them universal and you only need pick the correct spring height/load spec's to work best for an application. Many aftermarket heads will need longer than stock lengths due to port differences and deeper bowls than the stock stuff. Should also go without saying that a .600+ lift cam would need longer springs.. and therefore longer valves to avoid coil bind and guide/seal contact. Once you start grinding on heads/blocks and going to lumpier cams.. stock spec's for just about everything valvetrain related goes right out the proverbial window. But just to steer you in the general direction that you'll likely end up here anyways.. the general rule is this. Stock SBF heads can use stock valve lengths(4.91'ish lengths) for flat tappet cams up to around 230 duration and .550 lifts. This usually means that the valve spring will need to be a 1.7 inch installed height for proper seat loads. Cam Research will be the one to ask for confirmation of that though. It's also possible to use slightly lighter springs spec'd for 1.8 installed heights.. and/or shim and adust with + or - .050 keepers to reach closer to the 1.7 installed heights to achieve proper seat/open loads. For the intakes.. 1.94 may be considerably more common and actually cheaper in the long run because they cross over to so many other makes.. whereas the 1.90's are generally more Ford specific with fewer offerings/higher prices. My machinist usually only charges me about $1.50 per valve to quickly cut them down to whatever I want. The main benefit for me from cutting larger valves down.. is that the margins end up thicker(stronger and they flow slightly better).. and there's more meat to work with for back/face cuts. On the exhausts.. I'd probably just keep it simple and run the 1.6's if the new seats will allow it. Otherwise.. if the seats are too small to accept the 1.6's?.. then just cut them down to the max size that the seat will allow. If the cam is well over .500 lift and nearing 230 @.050?(which would be tougher on PTV).. I wouldn't backcut the exhaust valves as mid-range/top-end can suffer slightly.. whereas smaller cams will benefit from the lower lift flow increases and excessive reversion usually isn't a major concern anyways(bqackcutting exhaust valves allows for more reverse flow/reversion). With the exception of very agressive duration/lift cams.. most street engines will always benefit from back cutting the intakes. Another word of advice before ordering the valve keepers. Have the machine shop mock a valve and spring up to measure the installed height with standard keepers. Then order the correct keepers in + or - .050 installed heights to adjust for best preload/coil bind resistance while avoiding excessive amounts of shims or re-machining spring seats.
I've been reading this from the beginning and posted a couple times with suggestions myself. Sorry, but I have to rant, be patient please. I think it's great everyone wants to help a youngster get going. Don't loose sight of what he has. What he has for income, tools and skill level and experience and help. MY opinion is he needs to be working directly with a shop to do this build. He doesn't need to be on the internet asking the opinions of a bunch of people he doesn't know, or know their skill levels and experience, and that don't know him. He has already bought/cleaned stuff then decided to not use it for whatever reason. That is wasting his money. Money he has little of. My recommendation? Get hooked up with a local engine builder you can trust. Build a basically stock replacement engine. Put an intake/carb/exhaust on it and get driving. Do improvements as money allows. For example: If you want to change the cam, just realize it can compromise what you do with the car. IE Race cars don't use stock cams and vice versa. There is a reason for that. It also costs money to do it right and more in the long run to do it wrong. He should be buying a cam kit. Cam, lifters, springs, retainers, keepers, timing set. It all matches that way. He doesn't need a custom ground cam, he needs an off the shelf cam kit for a mild street engine. He's not racing, he's not got a ton of money to throw at carbs, intakes, heads, etc. He wants a little lope, good performance and a car to drive. Sure, I've spent close to $400 for custom roller cams for race motors, he can but a complete hydraulic cam kit from Comp Cams for less than the cost of that cam. Buy a 268H kit and go with it. Does he need forged pistons? No. How many of us with more "knowledge" started out first build with new forged pistons, aluminum heads, even a head swap for that matter, all new valvetrain, etc. It would be nice he didn't make some of the mistakes we made while learning, but he's still making mistakes with our guidance. He's returned pistons, changed heads, etc. We're confusing the issue as much as helping. He needs a basically stock engine, maybe an intake with a 600 Holley on top, headers and good ignition and cooling system. That's plenty on his budget and he can build his skills from that base while he drives it and enjoys it. If it has a good ignition and cooling system, it will accept improvements as he can afford them. Not aimed at any specific people except the original poster, not totally disagreeing with any of the previous posters. If you ask 20 people how to correctly build an engine, you get 20 different answers. He's asking thousands of different people, people he doesn't know from a hole in the wall, and spending his hard earned money on their opinions. Sometimes we forget where we started. JMO, SPark
I wouldn't disagree with much of that at all. We're just going by what he say's he wants out of the motor, is all. Had he said he just wanted a 275 horse stocker with bolt on parts?.. we'd have been saying to just refresh what he's got. But that's not what he said he wanted.. and that brings us to maximizing stock parts. Which means that by his definition.. he "needs".. ported factroy heads. Sure you can make somewaht similar power with uported stockers.. but the cam spec's are majorly compromised with peakier performance and MUCH less power under the curve. Since he needs to buy valvetrain anyways?.. it makes absolutely no sense to me whatsoever to try and save a hundred bucks when those little things will pay for themselves very easily in the long run. Efficiency WILL improve.. at least when he keeps his foot out of it. lol Heck.. the larger exhaust valve alone is worth 2mpg and 10 lbft all by its lonesome from reduced pumping losses. He "needs" compression. No brainer here as it improves just about everything and is THE best bang for the buck he can get from the broadest sense.. regardless of his intentions with the motor. Efficiency goes up and cost fro aquiring it can easily be offset at the pump. As for the "need" for a custom cam?.. IMHO.. no one short of a race team really absolutely "needs" one in the first place. But that certainly doesn't mean that it can't be worth it's weight in gold to someone wanting to maximize the full potential of all combined parts. It's not that much to have a custom flat tappet setup done. If you talk to cam designers and guys who run the off-shelf stuff before moving to a custom grind?.. they will set you straight on the gains that are possible for even a milder motor and wheterh or not is was worth it. Cookie cutter/generic cam grinds will give you similar to what everyone else is running.. which is fine if that's all you want. But if you want that last 15 horsepower and fatter power curves from a milder combo without resorting to excessive duration and lift to get it from an off-shelf grind?(can easily be well more than that on a higher end build).. it's money very well spent, IMHO. I do get your point though.. and many of us also came from meager beginnings where we had to make do with what we had on hand. What I have learned over time though, is this. What you think you saved on the front end.. ends up costing you far more than you thought it would on the back end. Obviously these are all only opinions based on personal experience and each build will have its own requirements. I just try to give best bang for the buck advice because it's all cumulative to make for a better running engine than all the others who just bolted theirs together. I also agree that the OP needs to work more closely with the engine builder and trust his judgement and skill level. Not many builders like dealing with customers who say.. "I read this on the net and your way doesn't seem to be the best for me". It pisses them off(the ones with bigger ego's even moreso).. and they are less willing to go that extra mile for you. They'll just toss yer junk together to get you out of their hair and front door quicker. On the other hand.. a good machinist who actually gives a damn about yer "junk factory parts" and the few hundred dollars profit that goes with it.. is MUCH tougher to find than you may think. Trial and error ain't very cheap either.. so I take all my parts to race shops and pay the premium prices they charge for better labor and machinery. Unfortunately.. basic rebuilder shops give you basic rebuild results. It's purely economics. Anwho.. some good points were made and hopefully the OP takes them to heart.
Well I've read it all and I'm just glad for the input. The amount of information here is amazing and before I started anything I just wanted some advice. Sure it's cost a few extra dollars but in the end, I'm hoping it will be worth it. I don't mind studying what everyone here says, (which is what I do) and from their suggestions I get what i think is best for me. It really helps open my mind to what's out there. And as for the machine shop, I've just been talking and listening mostly. They offered me an internship to learn machining over the summer so I do believe I may be on their good side. They're nice people and according to their website, they seem to be a race shop (but with more knowledge on modern engines than old) I'm working very hard on this project and I feel it's becoming the best I could make it. Which, hopefully lasts me a couple years... On another note. Those rockers I picked out... Will those work? Or are those not going to work on my heads? The cam manufacture is providing me with the springs they are suggesting so I'm hoping that will be nice. Plus they're breaking in the cam for me as well. Hopefully this will work out well. Looks like I'm getting close to completion. Just need valves, the last rod bearings, a ring filer, and the rest of the gaskets.... Maybe some oil too could come in handy. lol. Perhaps the new flex plate, a new ignition, and new hoses/belts. I think I might be close to completion then... From there I move onto power steering systems, new spring seats.. (Did a Shelby drop) and then fixing the transmission leak. Then its done.
You can wipe the ignition "wants" off your list. Take a stock reman points distributor,(single vacuum pod circa the late 60's) replace the points with a drop in electronic unit, fire it with a matching coil, Get an early 80's distributor cap and rotor set (post type with the small to large cap adapter) Get a set of Ford Racing 9mm wires and a set of Autolite Copper plugs. Cheap, easy, reliable and effective.
