hey guys i have stock 081 tpi 305 heads in my 355 with a tiny lg4 roller cam, stock springs, rocker arms and stock push rods. i don't know if i want to go bigger because of fuel mileage but here is the rest of my set up performer rpm intake, 1407 edelbrock 600 cfm carb, stock exhaust, a t5 and i have 12.5:1 compression. i will put a dp carb that flows more and has mechanical secondaries on eventually but for now i think that the cam is the enemy. i do know that the condition of the heads depends on the safe mount of lift but i am willing to assume that they are within tolerances. any cam suggestions will be appreciated

 

thats not good on iron heads

but to answer your question, 081 heads will tolerate about .470-.480 ish lift before the guide boss/seal contacts the spring retainer.

The only options you have is machine the heads for more clearance, or run shims and offset valve locks to raise the spring assembly above the guide. .050" offset locks and .050 shims will give you near .530" lift safely.

I'd get screw in studs first to handle that pressure. Else they will pull right out

 

i just added the head gasket and they are 10.8:1 compression thats not too high is it sorry for the false data i didnt think that it would make that much of a difference

 

small clearances like that when computing compression makes a huge difference

 

Its borderline, but it depends what cam you have. I was running 11.25 CR last summer with my 601s, but I had a relatively big cam too, so it worked out as long as the carb tune was pretty good and had the timing just right.

 

thanks Air_Adam and i like your avatar!

 

what cam should i use i would like to reuse the roller lifters unless that is a bad idea but it saves a wad of cash.

here is a link to the cams that i found some of then may be a little too large though
http://store.summitracing.com/Compar...SKU=CRN-109811

 

With 10.8:1 CR and a carb, you should probably be looking at cams with around 108-110 LSA (lobe separation angle) and duration around 224*@.050 or bigger. Lift won't really make a difference, as long as it works with your heads. You can reuse the factory roller lifters if they are in good shape and you buy a 'hydraulic roller cam'.

You'll want to run the engine fairly cool too, try to keep the operating temp between 180-200*F. I'd suggest a good quality GM or Stant 180* thermostat (no POS generic parts store ones, they never work right) and a Painless fan switch (200*on, 180*off). That setup works pretty nicely on my car. In reality, the switch turns on around 205* and off around 185*, but thats close enough IMO.

My setup when I had 11.25 was a set of 601 heads, 357ci shortblock, and Comp XE274 cam (110 LSA, 230/236 duration @ .050, .490/.490 lift) and it worked very well.

 

i am having a difficult time finding a cam that has less that .470 lift with that much duration and the correct lsa i was wondering what custom grind cams go for and who to get them from the best cam that i have found is lunati 50160 but i don't think that they make that cam any more

 

try my cam...

a comp 12-238-2

218/224 dur with .462/.469 lift its hydraulic flat tappet tho.

 

like i said before... just get any roller cam you like with less than .530 lift and run offset locks/retainers with shims. you will need springs anyway so upgrade retainers/locks.

 

i can change the springs and retainers by pressurizing the cylinder correct?
i do not know what you mean by shims and "offset" retainers

 

You won't find much in the way of long-duration low lift cams, but they are out there. There are some meant for racing that are supposed to conform to a 'stock lift rule' that basically means lift is around .410, but there are different ones that have duration figures anywhere from about 218* to about 246* or more. I couldn't say how streetable they are though, never tried one. Crane makes them.

Another option is the 'muscle car replica' cams that Comp Cams makes. They are just that - replicas of the old muscle car cams, like the LT1, Z28, L82, L79, etc etc... most of those cams have lift between about .420 and .460 (the hydraulic cams anyway - none are roller cams) and the duration is pretty good on some of them, like the L82 cam, but they are pretty outdated technology. They would work just fine, but are not the modern grinds that the XE series is for example.

Best option, realisticly, is to just have your heads machined to handle more lift, then find a cam you like. Those heads can be machined to handle .550 for sure, maybe .600 (just like my 601 heads were) without having to resort to goofy retainers, locks, etc. Its really the proper way to do it.

 

thanks adam it is always good to have a number of options and reliability is a must. i will talk to my local machinist about more lift but then i might as well do bigger valves and do a little porting. these 081s flow 195cfm intake and 135cfm exhaust at .500 so they'll flow pretty well after all that work but i think that exhaust may be in line before i start making that much waste! i still have the stock manifolds and every thing else so ill probably go 1 5/8" headers with 3" collectors then some day i'm gonna go TT so all the headers and cam will sort of be a waste of money but it makes it worth it just to built it up in different ways and see what i get out of it but these things cost money so it is a little bit of a pipe dream right now but i want to do it right the first time so research is the key here. i suppose that it is time to see what the head work will cost me and how much lift he will be able to accommodated so that i can find the right cam. thanks for all the help guys it is appreciated i usually can't get this much feedback let alone good feedback!

 

Exhaust is the first place anyone should start on a 3rd or 4thgen F-body. Get a good set of 1-5/8" shorty headers like the Hedmans if your looking for fairly good budget headers - I have them on my 350 and I like them alot. They fit well, plug access is pretty good, and they don't leak.

If you do the porting yourself, make sure you do some research here first - you don't want to just take out as much metal as you can. Volume is not what porting is about, and will just cause problems. There are certain areas of the intake and exhaust ports that require more attention than others to get the most out of them. There is a very informative thread by member "SittingBull" that will show you what you need to do in pretty good detail. Its not too difficult once you know what to do, but it is tiem consuming.

Having bigger valves installed is a good idea, but with the small 58cc chambers, don't have 2.02 intakes installed. They are too big, and cause shrouding problems with the very small chamber heads. Have the heads machined for 1.94 intake valves and 1.60 exhaust valves and you'll be good to go.

 

E-1134-P .290 .308 .435" .462" 273° 288° 198° 210° @.050 112LSA

E-1040P .291 .308 .437" .462" 269 279 202 212 @.050 112 LSA

E-1136P .308 .313 .462" .470" 288 284 210 215 @.050 110 lsa

E-1135P .320 .320 .480" .480" 306 306 230 230 @.050 108 lsa
needs 9.5:1+ hi stall and gears

These 4 ELGIN "ProStock" Hyd roller cams will work well.
http://www.elginind.com/

Similar cams available from under the Clevite brand. http://mahleclevite.com/
These Elgin part#'s are for 87 up roller blocks.

http://store.summitracing.com/partde...0&autoview=sku
TFS TrackMAX cam #31402000

270-276 214-220@.050 .452 .465 112 LSA

Once you've deshrouded the "081" combustion chambers for larger 1.94 1.60" valves, the combustion chamber volume will be bigger than 58cc.
Your cr will not be excessive.
Drill and roll pin the rocker stud bosses.
You can lengthen the stock rocker arms slot to allow more lift clearance using a die grinder. Do not make the slot wider or make it crooked.
You can grind the bottom of the stock retainers a little for more guide top/seal to retainer bottom clearance . Use Lunati #73943 springs for a mild hi lift hyd roller cam (drop on. 1.70" installed height Shim as nessessary)
Don;t be shy on the porting. These heads can work very well for you if you port them correctly.

 

thanks for taking the time to find those cams for me f-bird
and did those shorties from headman fit your y pipe by any chance because that would make it less of a stab in the wallet all at once if you know what i mean and how much better are long tubes?

if and when i port my heads ill mostly just clean up the mistakes that were left behind casting and gasket match, i have already read sitting bull's thread on porting and it was very helpful but i do not want to have to remeasure every port. Do you think that all the time spent removing the material from the heads will be worth while maybe to get the exhaust to flow better but it takes too long on cast iron if you ask me
but i am going to keep my swirl ports in case porting takes too long

side question i'm about to sell a 120k 305 short block and 700r4 on craigs list for $90 but the tranny only gets into 2nd is that a decent price? some guy wants it an hour after i posted it

 

it sucks that everyone is so spread out in such a way that it makes it hard to help each other out. I machine those heads to take as much lift as you could throw at them in about 15-20 minutes. It's a shame.

~Couch

 

yes it is very unfortunate, but you still can help! how would you go about this and what springs would you install and how much would charge? how much would you charge to do 1.94" and 1.6" valves and do you think that it is worth it as opposed to buying a set of heads for a few hundred dollars?

 

well I would put the heads in my seat and guide machine and use my guide boss cutter and cut the boss way down, then...blah blah blah....ok the back woods way of doin it is go get yourself a 1/2" drill from whoever buy a .530 guide boss cutter from comp or crane or manley perf. or whoever and an 11/32 pilot, for that kind of stuff you can get away with doing it by hand. Now for installing seat rings for 1.6 exhaust valves is about $10 bucks a seat. If I had a set of 081's I'd say I'll do mine and you just ship me yours and we'll trade for $80 plus shiping, and any other work you want done. As far as springs go use the springs that match the cam. Not necissaraly from the manufacturer of the cam but the right springs for it. What cam do you want to use? If you want my recomendation tell me what you want to do with the car and I can help you make it happen.

~Couch

 

well you are the engine builder ill take your suggestion on a cam over what ever i think may be good but it may be a few months till i feel like tearing my car apart again and or have the money but ill still be able to buy what ever cam you suggest when the time comes what do valves them selves cost don't take the time to look guesstimate and ill ask the guy around here who decked, jet washed and pressure tested my friends 300zx heads for $15 and ill see what he would do and charge and get an opinion from you guys
thanks for keeping the information rolling guys

 

Heres a basic porting guide. It will give you an idea where to work to get the best bang for your time. I don't know who's pic this is though.

 

thanks adam that will help when the time comes i saved it to my computer for the time being

 

when you start looking into porting contact me so I can give you pointers. You can ruin a head quick if you're not careful. As far as cams go I need gear, compression, head #'s valve sizes, RPM opperating ranges (drags, circle track, road racing, bonniville, etc.), weight of the car (approx.), transmission, converter, carb/intake system, and exhaust system.

~Couch

that picure above is an exhaust runner by the way

 

well i will give you all of the parts that i would like to have by the time that i do the heads and cam and maybe some that i will not have yet but will plan on getting. im gonna go with a holley dp with mechanical secondaries prob a 700 or 750,the intake it an edelbrock performer rpm (non air gap), ill do 1 5/8" headers with 3" collectors, trans is a borg warner t5 non world class i believe that the gears are 2.73 but i will probably go with...(add suggestion here). the car weighs about 3200 lbs and it will mostly be for roads so i believe that an operating range from 1500 to 5500 will be good but you would no better. the heads will be 081's they have 1.84' and 1.5 valves now and the combustion chamber is 58cc but i cannot get the exact CR the largest valve to go with is 1.94" and 1.6" as some one said before larger intake valve will shroud it in this combustion chamber.the problem is i do not know what pistons are i do know that they have 4 valve reliefs cut in them but the it CR is 10.8:1 not taking them into account.

 

as far as cam goes: hydorlic Solid or roller, sorry forgot to ask.

well Pistons are pretty strait forward it's dished, resessed, flat top, or domed. If there are no other fetured about your pistons they are probably flat tops. You need to unshroud the valves as it is. If I were there or you were here that would just be part of my valve job cost to you. You need seat rings installed to run 1.6 valves that's the big chunk o money you are gonna spend, unless you pay someone to port the heads. Now the only thing is being a 305 head it will not flow...crazy outstanding. Now contrary to belief you can get them to run pretty good on 350's any way. When you go to get wild with the head hogger 2000xlgtprz. Just remember that a little messaging can make a big difference so take it easy. Now it just so happens that I have a set of 305 heads that I have been doing work to on and off for just such a project...If I can find time I will go ahead of you and machine them in the manor that I would if you came to me and I can let you know exactly what to look for along the way...I think mine are 601's. Anyway when you go to start doing port work pay attention to the bowl area just below the valve seat you can narrow the guide boss some, but there is no reason to go crazy here, lay a head gasket on the head with some bolts in it after the heads been cleaned, but nothing else... start over... 1 go to machine shop and say "clean em, and mag em" nothing else, and when the guy starts sayin you want a valve job or whatever you say no nothing else. Then now you take them home and start gently messaging. You can spray a layout dye or paint or whatever on the head where it mates with the block allow to dry then lay the cylinder head gasket you intend to use on the motor on the head put some bolts in it scrbe a line in the sprayed on goo you used arround the entire chamber, and put the old valves back in it. Take your carbide burr, your rotary file, heaven forbid a stone grinder. and take the area aroound the valve pocket all the way to your scribe line, now don't take too much material out of the spark plug hole side thats where the 305 heads make their money just polish that area, just concentrate on the area towards the front and back of the head and that little corner right near the quench area. Pollish the roof of the chamber after removing the valves It's ok if you hit the seat with the sand paper rolls just not the cutters, when you change the valve sizees the seats change completely so pollish away if you run headers and can opt for D-port headers get the d-port gasdets and dye paint etc. just as above take the port out to the gasket line as before in the chamber justt do it the same way, then intake side of the head- Fel-pro 1205 gaskets same thing. Go too the line never over-if you go a little over don't panic just stop working in that area no matter how ugly it is. For both the intake side and the exhaust side don't mess with the floors of the runners especially the short side radius on the intake side, Just the bowl area the guide area and the port of the runner. You can posih anything just don't reshape those areas. Now for the last lesson horse power isn't pretty so if when you are done your 081's don't even resemble AFR 195's don't worry about it. If you did what I told you and nothing else then it will run good and no one will know they are ugly but you and me. Your motor isn't interested in flash or jewlry it only wants to go fast and sometimes ugly is fast. So after you are done is the machine shops turn tell them you want seat rings for 1.6 valves and a valve job for 1.94 valves take your valves with you if you have the money get a 5 angle vavlev job.

~Couch

 

so basically you are saying that my main concern is to do port matching, de-shroud the intake valves polish the combustion chambers, clean up the bowls and polish up the runners? I don't understand what you mean by "narrow the guide boss" and how much does a five or a three angle valve job help is it mostly for flow or seal? now i am beginning to wish that i had put my swirl port 187's on so that i could work on my 081's i think that ill start looking for another set so that i can work on them and drive the car and only have to tear it down and build it up once. are there any other heads that you would suggest that i could get off of a junkyard car that would be better than 081's? ill have to go to the junk yard and check out this eighty something c1500 that is by me i believe it had aluminum heads plus i have to go this week any how to get tires for my brother's car cant beat $20 you just got to find the good ones. thanks for the help!

 

the guide boss is nothing more than the sloped piece of iron that houses the probably still intragul(sp?) valve guides... meaning in the valve pocket area. If you wanted heads off of "maybe a junkyard car" I would suggest in an open chamber in this order: "487's", "993's", "441's", or even better the usually improved "X" versions. for ex: "487X." 336's were only produced as an "X" and they are also excellent open chamber heads...they were my first set ever. Excellent heads!! In a Closed chamber head: there were only ever two castings with ~64cc chambers with accessory holes in the ends of them the 186's, or the "291's" on either of those good luck finding them, and when you do be prepared to pay... I mean PAY. Unfortunatly my freind I havent researched 305 heads enough to give you an off the top of my head idea for which ones to use. Either way you go be they open, closed, or the even more closed 305 heads you will spend a lot of time and money to get them to do what a set of 67cc chamber World SR Torquers, or the even smaller chamber torquer 305's. For the low low budget builder those are a good conventional chamber head to use that still fits normal hardware Sportsman2's are even better. Even crazier are the new Iron Eagle heads, but they have bronze guides which are high quality, but don't do as well and I say that meaning that you just have to keep closser attention paid over a long period of operation(miles). For the money though besides the Iron eagles, and the sportsman 2's There is no head here I have listed that can beat out the Vortec heads for power, and there is no head here that can beat the Vortec heads in dollars spent or work done. 062's are a "light" head 96 and up, and they pretty well rock right off the shelf. Now the aftermarket heads will tear them up on the dragstrip, but they will tear up your wallet too. Be mindfull all the power you make reflects the cylinder heads you choose, so if I were in your shoes I would pick up a set of 062's, but here's the deal: they crack...all of them. (or so it seams) Now the good news: they all crack in the same place: If you stand the head on end on the floor if it's cracked it will be cracked parallel to the floor between the middle two chambers dead center the head cracked from one water jacket through the center bolt hole to the other water jacket. 5 angle is flow sometimes it makes a pretty good difference the school of thought behind it is that it helps shape the cone of flow at lower lifts... helps persuade the air to get in the chamber sooner and helps build up air speed faster. It also helps shape the charge cone around the valve in a more.... ideal shape.

...what lifter you runnin so I can get on the cam research for you.

~Couch

 

Well again that is a matter of which rockers are better and whether or not I "must" spend the money, all these things are pushing back the completion date unless we get that $600 check congress is talking about at tax return time. currently I am running stock rockers, I would like to stay with 1.5's because I can always get more lift out of 1.6's in the future... But you are a good sales man I can tell you have been doing this for a while any how, that makes me trust your opinion all the more. I feel that I need to tell you exactly what the car is used for so that you may be able to rule out what is excessive for my uses and... if you would be so kind as to make suggestions based on that, I have a tendency to get carried away but I have no clue how much power I will be making and money I, loosing. So the car will be a summer daily driver , it will see beachy areas and long drives such as road trips. so I need to take strongly into account that it must be reliable, fast, cheep, all weather and not quite as strongly fuel economy and that I spent only $400 on the car and welded up holes in the floor threw in a rebuilt 355 and a t5 that came as a package deal with the car. what I would like out of it is 300 to 350 crank hp and a reasonably tall 5th gear. the truth is that i would love some sweet heads and a huge cam but I don't know what I get in terms of reliability : price : hp. What would you do my car if you wanted those things or as close as possible, as a customer at someone else's machine shop. I am willing to do a great deal of porting and what not and I will be building the engine my self and lets say you had $500 what would you do in my shoes .