I am the proud owner of a partially assembled 73 Camaro sport coupe with a 307 and a TH-350. The engine starts and runs smooth, transmission runs well also. While I am happy that the car runs given its age, I do want to build it up a bit. The car is a gift for my father who love's 307's; due to my father's love of the 307's, I do not want to swap in a 350.

From reading several postings here and at deja.com, it appears that there are several basic mods which can be done to increase performance without killing the engine:

1. Edelbrock Performer RPM Intake
2. Holley 750 cfm Carburetor
3. Swap 305 58cc Heads onto 307 Block for better compression
4. Swap cam

I already have a Crane cam (P/N 10017) which has a 274 HO6 grind number and an advertised duration of 274.

I have already installed a set of Hooker headers with straight pipes.

This car is for fun and maybe a few challenges on the road....

Thanks for all your assistance,
TJ

Your welcome! It reads as a good start and gift for your father.

IMO, and this is just my opinion, I consider the 307 as a stroked 283. Therefore, I would probably use a 600 or 650 vacuum secondary carb and a High Energy 268 cam, maybe a Magnum 270 cam.

Hopefully others here will divulge their opinion(s).

There was a 307 build up just this month in one of rags, can't remember which one. Think it was Super Chevy. If I remember right, they put Edelbrock Performer heads, swapped the cam, intake and carb, and got 300 HP. Not too bad! I'll look tonite to confirm which mag.

The cam you mentioned sounds too big for a 307. A 750 cfm carb is definitely too big. Go with a 600 or 650.

Just stay small with the heads. Artie from TFS posted a nice 327 combo a week or two ago -- the same heads, cam, etc. might work good on a 307 as well. You might go a hair smaller on the cam though -- I would look at a cam with 220-225* duration @ .050 and a 110* or 112* LSA for a 307.

Will edit and post the link if I can find it.

Here it is

http://www.camaros.net/forums/showthread.php?t=75288&highlight=Artie

Many thanks to Everett, GHeatley, and Eric for their rapid responses to my original post. Your help is definitely appreciated.

I am getting the cam from my uncle who previously used the cam in a 305 with a QuadraJet on a stock iron manifold with cut heads. He said that it shouldn't be a problem, but it just wouldn't idle smooth. Crane's website lists the cam as working for 262-400 Chevy plants, so I didn't think it would be a problem in the 307. I realize that this is a very agressive cam, but I am not concerned with smooth idle and such. If it lopes, that's fine

I have purchased a set of 305 heads(casting number 14014416). From what I have read, the 59cc chambers should increase the compression, while the bigger intake port will help it breathe better than the stock 307 heads(1.72/1.5/75cc).

Given the previous comments here and elsewhere on Camaros.net, should I investigate a Holley 600? I don't want it to be starved at high RPM which is known to happen with 350's with similar setups. Also, given that this is a 307 and not a 350, would an Edelbrock Performer RPM generate better performance than a stock 350 intake?

Please excuse these questions if they seem uneducated; this is my first time working with this engine, and there is a general lack of information available.

Thanks again!

I remember reading on another post that the bore size is too small to let bigger valves flow properly. Hope the experts repond on this.

Sounds like your cam is used. Did you keep track of each of the lifters when they were removed from the engine so that you can match each lifter to its original cam lobe? If not, I would use a new set of lifters. Even then, your cam may wear prematurely.

How high are you planning to rev the engine? I would think a 600 cfm carb would be fine unless you are planning to go to 7000 RPMs.

The 274H06 is a schosh too big, but I wouldn't worry about it! CC's 268HE or Cranes 272/272 would be some better, imoh.. But it's stroke will handle any of the three cams...

I would instal a good old Holley 1850, 600cfm carb tho.

Get the CR. up to close to 9.75 to 10 to 1 and go have more fun than the Law will allow!

Please come back and tell us how she runs after you get her going!!

pdq67

[QUOTE=73CamaroSC]

Given the previous comments here and elsewhere on Camaros.net, should I investigate a Holley 600? I don't want it to be starved at high RPM which is known to happen with 350's with similar setups. Also, given that this is a 307 and not a 350, would an Edelbrock Performer RPM generate better performance than a stock 350 intake?

QUOTE]

I'm running a Holley 650 DP on my 302 and it doesn't even come close to starving so I'd recon that a 600 would work well.

yes, as gheatly recalled, there is a build up article on the 307 in this month's super chevy, they got 315 fwhp with a moderate amount of mods...

I built one with angle milled 283 super stock heads a WCFB and a very mild cam. It ran great but I think the compression would be too high for todays gas. Try 305 heads a Q-jet and a mild cam I bet you will be happy with the result.

That build up in Supe Chevy is a little bit flawed. If you read the article it says that they used the 64cc heads to get 9.5 compression, that's impossible on a 307. When I built mine I ran the numbers over and over and you need 58cc heads to get 9.25 compression. I went with a set of Trick Flow 58cc aluminum heads shaved to 50cc on my engine, but your 305 heads should work good. I run that exact cam in mine. I do have much better heads, but that cam screams in my 307. It idles like a monster though. You don't need the Performer RPM to feed that small engine, a Performer will work great on your set up. The 600 carb is just about right also, I run a Q-jet though. Don't worry about valve shrouding, your more than fine with your valve sizes, the 307 isn't that much smaller in bore than a 350 (not like the 305). Mine is .060 over which is a 3.935 bore. That's only .065 smaller than a 350's bore. Here's a little trick I found if you want to build a stout bottom end. Get a set of pistons for a 283 in what ever bore size you need. Now use a set of aftermarket rods for a small block 400 (5.625" if I remember correctly). Have your block shaved .020" and you'll have a .005" deck height. Don't worry about the shorter rods, with the shorter stroke it still leaves you with a better stroke/rod ratio than any production 350 or 400 (or even a 383) small block. Get your self a set of 1 5/8 headers and enjoy. I gotta tell you I love it when I whup up on a 383 powered car and then show then that 0020 casting number.

Give your dad a healthy 327 or 350 and he will forget all about the ship anchor 307!!! JMO Those motor never ever impressed me even supercharged although I do have one in a old ski boat and it runs decent. Im just giving you a bad time to each his own.......

My .040" over, hopped up 300hp/327 with the 272/272 cam had a 600 cfm Holley on it and I'm here ta say!! WoW!!

Stock, cast-iron 300hp/327, AFB 4-barrel intake and a cheap aluminum adapter to boot...

pdq67

TJ the 274H06 will have a very rough idle.You will need a 2500 stall converter or it will be a dog off the line.A Performer and 600cfm carb. would be a better choice or even a stock Qjet and factory intake.On a samll engine you need smaller ports to keep port velocity up.The 305 heads with the 1.84in and 1.5ex valves should be a very good match for the 307.Using 3.875 std. bore 3.25 stroke 4.100 gasket bore .015 thick steel shim gasket .025 deck clearence -5cc for piston valve reliefs 58cc heads gets you 10to1 comp.It should rip with the 274H06 cam and headers.If you need anymore help just ask.

I think Plum is telling you right!

go for it!

pdq67

I agree the 274 H06 will need the 2500 stall. I'd go ahead and install it. I've heard of people using it in 305s and being happy!

Sorry, my first post was incorrect. The 400 sbc rods are 5.585" long.

we use a boring bar and sunnen CK10 and take them to 4" bore, works great never had a problem, send me al your old boat anchor 307's

Lowcamaro I have heard from a few people that the 3970020 blocks will go to 4" without a problem.I have 3 of them if I ever need one.

the lighter the car the better with the small cube motors,had an old mechanic buddy that built a nice one for a t bucket roadster(original 1929 frame!)that weighed about 2440#.that thing was terrifying!nothing like 110mph on a country road with no seat belts and about 4" of fiberglass body above the seat line to hang on to!GEEZE!
where are you located?i have a set of #601 305 heads that are completely bare i'd give ya,these heads can be ported to rival the vortec's i am now using!they are about 58cc but i'm not sure how much mill they could take.anyone?the valve seats were redone a few k miles ago and the surfaces are flat,though it seems one of the #8 cyl guides might need replaced.still,a great building block for your motor!you could even go to 1.94/1.60 and be ok if you really want it to rev!but build that bottom end well.
Eric B

1.94 valves hurt the flow in a set of 58cc stock heads.The valve is to close to the combustion chamber wall.

Thanks for all your posts! You have all been quite helpful. I have acquired a set of 58cc heads from an 86 Z-28. They are 1.84/1.50 intake/exhause with casting number 14014416. I have also obtained a stock 4 barrel intake manifold and Holley 600 (1850-4).

On the cam question, a friend has offered me a 302H Fireball Cam from Crane (P/N 114822). I don't know much about Cams, but this seems even wilder than the 274 cam I was planning to install. Any comments?

Also, the tranny gave out on Sunday while on a short test drive. We believe that the car had been up on blocks for 3-5 years, so this was not a surprise. The previous owner did in fact run the engine periodically, and the engine is in much better condition. The tranny is a TH-350. I have three options that I can see at this point:

1. Rebuild 350-how tough is it? how much would it cost to have someone else rebuild it for me?
2. Swap in a 400-how tough is it? Is the 400 worth the extra work for such a small engine?
3. Swap in a 700 from Bow Tie Overdrives

Please let me know your thoughts on this.

http://www.geocities.com/greengoblin73camaro/index.html

A TH-350 is more than tough enough for a well built 307. With minimal work they can be built tough enough for 11's in the quarter mile.

The 302H is too big stick with the 274H06.Rebuild the TH350.