I have a 1986 Trans Am 305 24 LBS injectors Headers, 2300 Stall, 3.73 9-bolt gear. My uncle had a pair of 305 H.O. Heads and they are in need of a good cleaning and a valve job. But are the H.O heads worth wasting my time, or should i leave my stock 305 heads alone. And what kind of cam should i get if it matters non-roller

Thanks


Any other mods ideas are welcome

 

Anyone???

 

I think L69 heads are the same as LG4's. Its the pistions that raise the C.R.

 

Yes, they both use the same heads, but there are two different 305 HO heads out there. The 416's and the 601's. Pop your covers and see what you have, then see what those other heads are. Here's the deal, 416's and 601's have the same port dimensions on both sides but the 601's have the High Performance combustion chamber design, which is kinda kidney shaped rather than the usual D-shape. This is the same chamber design used on the best of the Camel Humps out there, along with the 041/041X's and many aftermarket heads.

If you have the 416's now and he's got the 601's, do the swap! But first do all your port work... gasket matching, bowl blending, etc., while focusing on freeing up flow rather than actually increasing port size. After this is done, take them to a good shop and have them cut for 1.94"/1.60" valves along with a 3-angle valve job.

When gasket matching the exhaust ports, only match the ceilling and walls, not the floor. Slightly radius the lower lip left behind. This will increase velocity while diminishing the effects of backpressure in the hedders or exhaust manifolds... The best of both worlds essentially. There is also some theory about this producing a vacuum to aid in evacuating the exhaust charge. I can't tell you for sure wether this is actually happening or not but I can tell you that this modification BY ITSELF it worth some noticable gains. And remember, you don't need to gasket match "big", measure your ports and use a gasket that is nearly the same size. I tend to use FPP-1204 for the intake... FPP-1256 in your case (same as 1204 but with open heat crossover), and FPP-1404 for the exhaust. This is assuming 1-5/8"-1-3/4" hedders. If using 1-1/2" hedders or manifolds, use an FPP-1444 for the exhaust.

While doing port work, remember to focus on keeping all ports the same volume and evenly shaped. Once the majority of the work is done and the valve seats have been cut, but before polishing, go back and "CC" the ports to see if any evening up needs to be done. You will need the valves in to do this. I like to use break in springs for this as they are able to be installed and removed by hand, without any tools. Don't worry about shims and all, you'r just using the valves to keep the "CC" fluid in.

Another mod worth spending your time on (which I just referred to) is FULLY polishing the exhaust ports and combustion chambers, but you may want to do the chambers before you have the valve job done. Radius any and all sharp endges prior to polishing the chambers as this too will aid in reducing hot spots and increasing flame travel. The more mirror like you can get the surface the better... same goes for the piston faces. I actually take it to the point of using several different levels of polishing compound at the end.. you wanna talk about a mirror finish!?!?

Don't forget to match the bowl throats to the new valve seats on both the intake and the exhaust prior to polishing, all the time BEING VERY CAREFUL (as though your life depended on it) NOT TO TOUCH THE VALVE SEAT WITH THE CUTTER!!! If you touch the valve seat you're screwed and the valve job will need to be redone. Covering them with some duct tape is not a bad idea, and can save you from a VERY SMALL and LIGHT touch, but anything more will require having the valve job redone, which will probably mean cutting a new valve seat.

All of this will have these heads outlfowing a set of Vortecs, and port velocity will be insane. I have run these on 383's with VERY NICE RESULTS!!!

So yeah, there's the skinney... for the cost of the seat cutting and parts, along with some well spent time, you could have a set of heads that will produce GOBBS of dependable power and worth keeping for a nice long time.

Hope this helps!

- Penix

 

WOW Penix,
That's a lot of good info.
Whenever I work on my car, I write down the part numbers I find on the inside cover of my shop manual. My 83 has the 416 heads.

 

Well thank your for the info, but i found out that my heads are 416s. I have a 86 and GM put the smallest cam in the motor, so i want to replace the cam. And right now whenever i start my car smokes comes out sign of bad valve guides. And my mom and dad told me that i'm not allowed to put a cam in, so i was going to tell them that i was going on a trip with my freinds when i really am going on a trip to my freinds house which is down the block, and so i wanted to talk as little as possible to put the cam in and i dont' have enough time to pull the heads and rebuild them i wanted a pair of build heads to switch them out really quick, Are the 416s heads any good? are the better or worst then stock 305 heads? any advice at all would be great

 

I'm not sure if you didn't read my post all the way through or what... To sum it up, two of the best heads GM has ever produced for the 305 are the 416's and 601's, the 601's being the better of the two. Both of these are considdered the 305 HO heads.

Look into getting a set of 601's off e-bay. It's common to find them already built with 1.94"/1.50" valves and a 3-angle valve job. In this state alone they will provide a noticable difference. Have them shipped to your friend's house then when you're swapping cams swap the heads too, just be sure to use the right gaskets and torque them down properly.

You also have the option of throwing on a set of Vortec heads, but you'll need to get a set already drilled and tapped for screw in studs and guide plates, and you'll need the matching intake and valvecovers too... there's more but I'm only getting into that if you're really interested.

Also, let me know what you've got in mind for a cam, I know most young guys tend to go a bit too big... we've all made our mistakes, that's how we learn, but why not benefit from other's experience when you can, right? Most likely, you'll want something with say a 212/218 duration @.050" and around .450" lift with 1.5 rockers.

Let me know what you've got on your mind.

 

I have a 2200 Stall so i wanted the cam for like around 2000 to like redline so i have had two cams in mind, One from summit and a Crane one.

The summit: Summit Part # SUM-G5000

Up to 40 more horsepower for your TPI engine


Chevrolet: 1987 and earlier Camaro/Corvette 305/350, 268/278 degrees duration, TPI camshaft kit

Stuffed in a 1986 IROC Camaro with a 305 TPI engine and an computer chip, our TPI cam kit made 40 extra horsepower and knocked almost a full second off the IROC's 0-60 times--and the computer worked perfectly. This kit includes the cam, lifters, springs, retainers, and lube. If your car has more than 30,000 miles, we suggest you add a new timing chain.


* Advertised duration: 268 intake/278 exhaust
* Duration at .050 in. cam lift: 204 intake/214 exhaust
* Gross valve lift: .420 in. intake/.442 exhaust
* Lobe separation: 112 degrees
* This cam kit is designed for Pre-1987 non-roller camshaft TPI engines

***** No Powerband rating


AND
The Crane: Summit Part # CRN-100052

Buy a cam, get the lifters free!

Chevrolet: 262-400, 272/272 advertised duration, hydraulic, cam and lifter kit

This Crane Energizer camshaft gives you more mid-range power, added torque, and better throttle response at a price anyone can afford. Plus, you get the lifters free! The hydraulic camshafts are computer developed for non-emissions controlled vehicles with tighter lobe separations and single patterns for a lopey idle quality. Kits include camshaft lifters and assembly lube.

Specifications:
* Advertised duration: 272 intake/272 exhaust
* Duration at .050 in. cam lift: 216 intake/216 exhaust
* Gross valve lift: .454 in. intake/.454 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 2,000 to 5,000
* 8.75 to 10: 1 compression ratio recommended


Which one of the two, if any, do you think is good

Thank you :hail:

 

Actually, I think you'd REALLY like that Summit cam, which is actually made by Crane cams anyhow... Yep, Summit cams come from Crane.

A cam like this should begin picking up around 1600-1800 RPM and fit that 2200 stall PERFECTLY!!! You should get plenty of top end without low end lag for lack of torque. It should also work very well with your stock compression ratio...

I'll run some numbers and see if I can't give you some more accurate info. As things stand right now though, I'm opting for the Summit Cam kit.

BRB

- Joel Penick (of "Penix Bowties")

 

Yeah, I think you'll really like the Summit cam... I ran some numbers and you'll be making nice use of that little 305. Along with this cam I'd throw in some 1.6:1 roller rockers, they will increase both low end and top end performance, along with adding some usable RPM up top, which would be nice with those 3.73's!

What ever you do with the heads, make sure you keep the same size combustion chambers, and mic the old head gaskets before buying new ones so that you can match those too. You don't want your compression ratio dropping any, but at the same time, it it goes up more than a couple points you'll most likely run into detonation problems.

Have you looked into installing a 180 T-stat? I know it requires play'n with the computer but it'll make a noticable difference, as would installing an adjustable fuel pressure regulator and kick'n it up about 4-5 lbs above stock. If you do play with the computer, also look into having your fans come on a bit sooner, say on at 200 and off at 185.

I'll see what else I can come up with. I've always enjoyed pump'n up 305's

- Penix

 

Thank You for all the info. I it is really helpful, I so to the Chevy's Shops and they only find a cam for me, they never say lift, powerbands or anything like that. THANK YOU SO MUCH

Anyhow... I do have a 180 Therosat and the chip that turns the fan on at 200 and off at 185 . 24 LBS injectors with pressure reg headers custom cold air and well the gear should have gone in this weekend, but things came up and he can not do this week, so i have to wait untill the weekend after like the 5th or the 6th, but he is doing everything for like 150, so i'll wait.

Also the Trans Am fund is running low, so time isn't really important but Thank You, for the info, i have printed the whole post and filed it so that i can use it later