i'm fixing to have my heads ported on my 86 305 tpi motor and was wondering what performance gains i could expect from going to a 1.94 valve. is it really necasary to do this for the power you are going to get. the motor will have a cam and ported intake. thanks for any input.

 

Due to the small bore, 1.94"/1.52" intake/exhaust valves are the largest you can run in a 305 without notching the cylinder walls. of course you could run smaller, but if they are close in price, why not go with the biggest you can run?

 

The 305 shrouds at much more than that I think. I would get 1.94 to ensure it's not a bottleneck later on.

 

Whats the average price for porting 305 heads, and getting 1.94, 1.52 valves. machine shops are scarce aruond here.

 

I read a tech article in one of the mags that said 1.94 valves on a 305 actually decrease airflow, not increase it. I suspect it's a result of shrouding.

Jake

 

I'm looking for information on this as well, since I'm going to pick up a spare set of 305 heads, build them, put new springs(matched to my cam) and get new valves and port/polish them....I also am looking for this information.

 

I'll see if I can find the magazine that has the article on building the 305 and I'll post it. I don't remember which mag it was in, and I've got tons of them, so finding it may take some time.

Jake

 

Thats ok...I still have to find a set of heads anyway, b/c my TA is my daily driver. My plan is to do the heads while i drive the car and have everything done and then do the swap along with Hooker 2055's. You can post it/PM me also whenever you find that article. Thanks.

 

Okay, I will.

Jake

 

400 horse 305 build up. They used 1.94 valves in this engine build up to make 400 horse.

From what I've seen on a flow bench, you do get some shrouding from the smaller chambers/cylinders of the 305 compared to a 64cc or 72cc head of a 350, but the flow numbers are still higher than the stock 1.84 valves. You can also minimize the shrouding if you puch the cylinders out .030 to .060 as well, then match the chambers. This is what I'll be running on my LT1 305 conversion along with an SLP cam of undetermined specs...

 

.....I just want to be certain of something...was talking to someone tonight, a mechanic and he kinda gave me the scare about porting/polishing these 305 heads....I definetly dont want to kill my bottom end power/torque and have everything up top only...I mean its not like i want to go crazy on the porting....but what i need is a realistic expectation of what will happen when i redo my heads....porting, polishing, all new performance parts, and hooker 2055's in addtion to my existing mods which are in my sig in one of my earlier posts....I just dont want to get all the way into this and then end up loosing bottom end 1xxxk-5xxxk power....its not a bracket car, and the only racing it woudl see is 1/4 mile track time and daily driving...highway and around town. So if someone could reassure me and get the scare out of me, that would be great....from what i read so far, i have made the assumption that there will be many a smile on my face, and many a pair of underwear to change.....thanks.

 

Porting will help power all around since airflow = hp. Whether it will be a high rpm motor is based on your cam selection. A 204/214 or 214/224 cam works quite well in a 305. The first one makes good low end, the latter makes more midrange.

As far as the bigger valves go, I don't know if I would put bigger valves in unless the seats need ground, especially if this is just a mild motor. Now if you were building for max hp (why out of a 305 I don't know, but we'll go in theory) then I would definitely get 1.94/1.55 valves. Just FYI, I'm doing a budget build on my 305 and I'm keeping the stock 1.84 valves (heads are ported of course).

 

Thanks for the quick reply. The main reason I am doing this right now instead of the insane 350 I plan to do in a couple years is b/c this is all just a guinea pig...and I want to do alot of the work myself.....i want to learn how to do things...when I did my cam, and timing chain, lifters, fuel injectors.....it was all something i learned b/c i spent just as much time in the garage working on it as my mechanic did. So I'm doing this mainly as a learning expereince and also just to get some more power out of this 305.

ANYWAY....like i said, the cam i have in my sig in one of the above posts is what i plan on keeping in there. I already found the matched set of springs for it from Crane. I'm looking for low end power, since this will be a daily driver around town and on the highways and will see some track time in the 1/4mile just to see what it can do after i do the heads and headers. It wont see ALOT of track time. So basically, low end is what i'm shooting for mainly.

Could you just explain the valves to me a bit more, particularly about shrouding and the 1.94/1.55 valves? With the mods i have in my sig below, and my intentions as you know them now, you're saying I should stick with the stock sized valves? If that is the case, what kind of hp figures should i expect from doing the heads as well as the headers? And going to the bigger valves would, as somone mentioned, actually decrease power, not increase it? Not good. I just want to be clear so i dont make a big mistake or not really gain much. I want to get the most power I can from doing this "experiment." Thanks.

 

There's a guy that just put P&P World SR Torquer heads on his 305. Those heads have 1.94/1.50 valves and can be made to flow marginally better than the stock heads (if both are ported and polished). It's a bonus that he did it with a stock bottom end and a stock TPI set up (with headers, dual exhaust, cam swap, and the heads). Here's a link to the thread in the engine swap forum. 306 HP at 5100 and 366 TQ at 3800 305 build up.

 

Wow.....nice #'s there...just not sure if i want to go spend so much on a set of heads...i might be able to get them done cheaper myself.

 

.......to do my heads myself(get a set of 305 heads, send them out, have all the work done, rebuild them, install them) or to get these World SR Torquer heads and then just put the springs that match my cam on them? I'm asking this in relavance to cost....cost of doing the heads myself vs. cost of buying already made heads? Still would want a port/polish job. I'm also planning on the following in addition to heads on the 305:

*Hooker 2055's
*Siamesed Runners
*POSSIBLY a more aggressive cam than in my sig
*POSSIBLY a larger throttle body(but i read somewhere that said they arent worth the cost for the TPI motors)

Advice please?

 

I understand doing mods to your current motor, it's a great way to learn (same way I did and look where I am now), plus more power is always good. For lowend, that's a good cam. I'm guessing it's 194/204 duration @ .050". You could step up one level to 204/214 duration that would give you a bit more lowend since the 194/204 cam is pretty small. As far as the valves go, the stock valves will be just fine with what you're doing. You could go with bigger valves, but to be honest it will be wasted money. You won't gain much power from that. By porting the heads and getting headers I think you could pick up 40hp or more (assuming you're have a good cat-back system).

 

Yea, its definetly a learning experince...I see myself doing this in the future over and over again as a hobby, so why not gain some experience on it now, as low-budget as possible? Thanks for the advice on the valves. Your guess on my cam spec was right on the money: int: 194 ex: 204 for duration, and set at .050". :thumbup: But now, as my thirst for more power comes, and from reading other posts, doing research, etc, i await a comment/answer/advice on the new heads(304 S/R Torquers) vs. doing my own 305 heads, and the runners coupled with the headers as other bolt-on mods. *Oh...and the cat-back system until I add the Hooker 2055's consists of a Random Tech High Flow Cat, and a 3" Flowmaster American Thunder System.*


Any specific cam you want to reccomend? Still want to stay computer friendly....I am partial to Crane Thanks again.

 

Well, there are advantages and disadvantages with both heads, so first off I start with the S/R 305 Torquers. First off they're a brand new casting, so you know they're not warped or the guides are toast or anything. Second, the springs that come with them will work fine for almost any cam you would want to use (I think up to .500" lift). IIRC they come with screw in studs, so no need to worry about that. They also come with 1.94/1.50 valves. Now the downsides, first they're not cheap, especially for being Stock Replacement heads (S/R). You could find a set of reman'd heads for much less that are nice for much less. The ports are very similar to stock ports (although what casting, I don't know) so they would still need porting to flow some decent numbers, so figure the cost of the heads, plus whatever it costs you to port them ($300 or so for a shop, or $50 in materials for you).

Alright, now the stock heads. Chances are they're not warped and the guides are fine. That can be checked at a machine shop after they are hot tanked. You should also have them magged while you're there and shaved just enough to make the deck surface level (that is if they are slightly warped). The rocker studs should at least be pinned, but you can also have them tapped for studs. You can pin them yourself, FYI. The valves will need lapped in, just to make sure, and of course all the valvetrain parts need to go back to where they were, so bag and label all the parts. Like said above, they will need to be ported to flow some decent numbers, so that will cost a bit. I think that's all for the stock heads.

Personally I would stick with the stock ones. You'll save a bunch of money (that can be put into the motor elsewhere). Also, just a word on those heads, they're not bad, but I wouldn't ever use them. For $200 more you can get a set of Dart Iron Eagles which flow way more than the S/R's, so why not go with those for a bit more, but that's just my opinion.

As far as cams go, I think you would be happy with the 204/214 cam (since you have TPI). It will give plenty of low end grunt and good midrange. I know you're partial to Crane, but Summit has cam kits for $80 (compared to crane's $120) that are just the same. I've used a few so far and I'm very happy with them, I think you would be too. The Summit pn is SUM-K1102.

 

Kfoley....

Thanks ALOT for the information and explanations. That helped me out alot. I'll probably be able to get a set cheap or for nothing....so i'll end up re-doing a set of 305's. Someone mentioned to try to go for like a 90 350 head, b/c they are like vortecs...not sure if he knew what he was talking about.....need a bit of input on that.

Thanks for that summit part#.....just want to be certain if that is ECM-fiendly? I appreciate all the help....this should be a fun learning experience for me. Thanks again.

 

Hey, no problem. I started out the same way as you, and people helped me out, so I feel I should do the same now that I'm somewhat experienced.

Anyways, if you do a set of 305 heads, make sure not to get TBI heads. They're also known as "swirl-ports" or as most of us on here call them boat anchors, that's how bad they are (performance wise). They're not bad for street driven, stock setups, but for performance apps you want to use anything but them. The 305 TPI and carb heads (416's) will flow about as well as vortecs when properly ported. If you have a chance to get a set of vortecs, I would go with them. They flow very well out of the box, in fact porting them will only net a few cfm's. Full porting (port reshaping with welding) is required to see any major gains. Vortecs came on trucks '93 and up IIRC, but I very well could be wrong. The only thing with the vortecs though is that they have 64cc chambers, which will kill your compression on a 305, even with flat tops and shim gaskets. That can be taken care of by shaving the heads a bit (although I don't really reccomend that, but that's just me). Also, with the vortecs you will need a vortec style intake (which SDPC sells).

The cam I reccomended is ECM friendly, in fact I'm running it in my truck (350 TBI) and it runs very well, even w/o any tuning (which I'll get around to someday).

Well, I think I covered it, if I didn't let me know, or if you have any questions I 'll be more than happy to answer them.

 

TONS of helpful info you have there. I'm particularly thankful that you told me about theTBI heads.....that saves me tons of headaches. I'll look for something with the 416 casting #. I already put the word out to my friends with shops/junkyards/etc...so I expect hopefully a response soon. Good thing that cam is computer friendly....will look for it in the Summit catalog. I also plan to get into prom burning someday myself.

When I go to porting and polishing my heads, I dont plan on opening them up alot when I port them....I dont want to kill my low end power. All i'm looking for is mostly low end, and midrange, and maybe just a bit up top....nothing more. I'm going to skip the vortech heads, b/c I want to keep the stock TPI intake....so I'll just get the 305 TPI heads....but you mention not shaving the vortechs.....what about decking the TPI heads for a BIT more compression......like .100 or something like that? Someone I was talking to last night in the auto parts store where I work mentioned that to me. Of course, that would be done in the machine shop when i have them sent out to get magnafluxed, tanked, etc....what is your opinion about that? Thanks for all your help again.

 

Seems to me like a little bigger cam would be good. Say like the Crane powermax cam 2032 (P/N 104224)
(in. 452 ex. 465) (in. 214 ex. 220@.050) LSA 112

 

I have the crane powermax 2020(P/N 114112) in there now.....the LSA is supposed to be 104. I edited my message and put this information in....that my LSA is 104, and i want low-midrange power and a bit up top.....and I dont mind a lopey, meaner sounded idle/car, and would actually prefer that, so as long as the car doesnt die out on me and I can depend on it without causing problems. I dont think the 2032 would work in my car since its an 86, not an 87 and up. Thanks again.

 

TTT

 

Sorry it took a while to get back to you, I've been pretty busy with classes and work this week. When you port the heads, don't worry about opening them up too much. With the stock castings you would have to bust through a wall before you affected the port velocity enough to hurt low end power (which would be miniscule). Just smooth everything out and think about how air (or water) would flow through the port. Pay special attention to the seat and the short side radius, that's where you'll see the majority of your gains. You could shave the heads, but .100" is quite a bit. IIRC .010" of deck surface = 1cc, so by that thinking (once again assuming it is correct) that would put you at 48cc's, which would be way too low and would shoot compression into the 11's/12's. I would stick with the stock size chambers (assuming the motor has flat-tops in it) and use Fel Pro 1094 head gaskets. That should put compression about 9.8:1, which is perfect for pump gas.

 

I know what its like to be really busy....no big deal. Basically, what you're saying is I shouldnt deck the heads at all? I understand what you said about going too far with it, but was curious about decking them just enough....just in case the heads are warped or something else afflicts them. I have always run and will always run 93 octane gas in that car. Eventually, I will print out this post b/c the information you've given me is resourceful and will help alot. Just a quick ?.......305 TPI heads have the 416 casting #.....whats the TBI head casting # so I dont pick those up? Thanks.

 

I wouldn't worry about decking them as long as the surface is good. If it's warped (ask the shop to check) then they can shave them just enough so they're flat again. Like I said, chances are they won't need it. The reason I don't like shaving them is that it makes the deck weaker (aftermarket heads don't have much problem with this, but stock ones don't have a real thick desck surface), plus down the road when you want to put the heads on another motor (even if you don't plan to now, you'll eventually find a use for them) you'll kick yourself because the chambers are so small and can only be used on 305's or 350's with dish pistons without making compression really high. Just so you know, you should run the lowest octane gas possible, otherwise you're wasting money and (fractional) power. The higher the octane, the slower it burns, which means less power. It is required in higher compression motors though because the high compression heats up the air/fuel mixture that it will self-ignite (detonate) with the lower grade fuel. The higher octane fuel burns slower (and requires a slightly higher temp to burn) which allows you to run more compression. Most people equate higher octane to more power, but most times it's the opposite. The extra power is gained from the higher compression, and with that you have to run more octane. Another myth is octane booster. In actuality it only raises octane a couple points at most, and what costs $5 a 8 oz (or whatever it is) bottle costs about $3 for a gallon at a paint shop and it does the same thing.

Sorry about the length of that, I just wanted to clear up any confusion you might have had (if you did at all)...

Anyways, the 416 heads came on 305 TPI, and the LG4/L69 (carb) motors. I did some searching on Mortec, but couldn't really find out which numbers were swirl ports. There were a bunch of numbers. I think 081 heads are good though... The best way to find out is to pull a valve, but I would do that anyways before you buy them.

 

Once again, thanks for your help....all this info saves me, as I'm sure you know yourself, a crapload of headaches. I never knew that about the octane of fuel....thats news to me. A couple years ago, I tried running 87 and 89 octane in my car and i could swear it had a bit more pickup/power.....but it also pinged.....i only used it for a couple weeks....so after that happened, i went back to 93 octane and never went back.....so i dunno...before I knew better, I tried that octane booster....did nothing.

I will have the machine shop check them like you said. If need be, they can shave them just enough. I'll be looking for the 416's.....I have several friends with their eyes/ears open for them now also. Like I said, i could probably get a set of stock ones either cheap or free. I'll soon find out.

 

If you're running more timing, it could require higher octane fuel to fight detonation.

The heads should be pretty cheap. Most people will almost pay you to get rid of them. With a little work though, they have a lot of potential...

 

I had to run a BIT more timing for the new cam that we put in there....I just dont remember how much we advanced it....I might try 89 again one day see what happens....if it pings, i'll go back to 93.

I just hope we do the "little work" the right way....thats all i care about. But my friend knows what he is doing. The fine tuning will be the challenge after everything is back together.

Also, someday, THIS will be my challenge for this car: http://www.sallee-chevrolet.com/Chev...ckV8s/572.html

 

You might do a search for porting 416 cylinder heads, Sitting Bull did a write up on it a while ago, it's very good for beginners and takes you step by step. You shouldn't have any problems though, it's not as hard as some people make it out to be, just take your time.

That's a nice motor, I didn't know chevy made it... Only bad thing is it's a tall deck motor, so there will be some clearance issues, but nothing that can't be taken care of.... I'm hoping to build an alky 496bbc for my drag car this summer, that should be fun....

 

Once i find some cylinder heads to work on, i'll be doing ALOT of searching...either find a set of heads of find a winter beater car.....so that this one can be torn down to work on the heads....i almost had a good one for $500 but the guy gave me the wrong phone #

Yea, that motor is bad@$$....but anything is possible:hail: Just would want a really good F/I system for it. That 496 sounds like a really awesome project....on alky too.....:hail: :hail:...just make sure you dont give it Bacardi 151...save that for the victory parties

 

....that summit cam part # you gave me.....SUM-K1102.....i know its more aggressive than the Crane one I have in there now, but I was just wondering what the RPM range is on that cam and LSA? I think my Crane is 104....and the RPM range is 1-1100-4000 or something like that. Would that summit cam also SOUND more aggressive than the Crane one? I noticed a different sound when i put that cam in there....just was wondering if it was going to sound/perform more aggresively. Thanks.

 

after some research ive decided and got a good deal 50.00 for new cam and lifters to go with the crane compu cam 114132 210/216 440/454. im also porting my heads and intake and all the usual bolt ons. im building this for a good street car. this is a good cam for a 305. if you think this is to big you could step down to a 114122 204/214 423/446. but i would go with the 114132 and do it right the first time. the comp xtreme energy cam is also a good choice 212/218 449/456. im also running 3.23 gears and crane and comp said that would be fine for there cams and are computer friendly. hope this helps you.

 

Thanks...that does help somewhat. THe cam 114132 with my gearing of 2.77 wouldnt work for me as it would for you. Thats mainly mid and upper rpm range, i need it for low end and mid. I think thats what the summit part # i was given by Kfoley was for. But i still would like to know if i went to that more aggressive cam, would it also make a difference in how the engine sounded? Given the fact that its loud now and I'll be doing heads and headers as well....

 

I have been running 2.02/1.60's in my 305 for the last 3yrs with no additional cyl work so dont always belive what you hear!

 

Are the guides repositioned closer together or what??? What casting heads are you running them in?

 

Cant remember the casting# I will try to get it but they are a set of mid 70s smog heads that are bored out to 2.02/1.60 then ported, the guides were left in the stock position when I got them set them on the block because I had heard the same thing that you couldnt use 2.02's but both valves cleared just fine

 

On Summit's part description is says 1500-4000rpm, but that would be in a larger motor. In your 305, I think you would see 1800-5500 or so. The LSA on it is 112. It would sound more aggressive than the Crane one, there would be a slight lope to it (if you listen, or if you're running duals it's noticable). It will perform more aggressively as well, but it's not really wild or anything like that. Good cam for midrange in a daily driver 305.

 

Nice....thanks :Thumbsup:....my Crane cam is 1000-4000 rpm i think....so the 800rpm difference wont really do anything negative....i mean, I'll still have plently or low-end power..especially after the heads and headers, right? Not trying to sound stupid, just dont want to end up kicking my own @$$...

 

Nope, it won't do anything negative. You'll make more power throughout the entire curve. After you do all this work, it's going to be like a whole different car compared to the stock setup...

 

Awesome. Now I cant wait to get going with the mods....my mouth is watering....