As some may know I planned on doing a cam swap this spring, but money has gotten tight right now, plus the fact that I want to do a few minor mods to my tranny to help it's 1-2 slippage (that should help my 1/4 significantly).
I was planning on getting the Comp 268XE cam, since I still have a stock converter.
So I might push the cam swap back to next spring, now to begin my question, I had planned on having my heads ported and a higher stall TC as well next spring. I feel like it might be best to wait to do the cam at the same time, that way I could match my parts better.
So, what do you guys recommend I do, I want to go with a Comp Cams,but which one.
I was going to order the home porting head set from Summit for my heads, my brother has done this before so he'll do most of it. What else would I have to get for the heads, which size valves should I go with, I know the larger = more airflow, but I assume there is a limit for a specific application, I hear 2.02 talked about a lot, so what do you guys recommend I do, also should I buy new springs, pushrods???
Now if I can beef up the heads a bit I can go with a larger cam, correct?
Now for the final part, with a larger cam, ported heads, what kind of stall TC should I get?? I want the best acceleration possible without destroying my mpg, right now I get about 18mpg, I wouldn't want to drop below 15mpg.
So, can you guys help me out some?? I would really like to be at 13.00 in the 1/4.
Thanks.
Oh, forgot one thing, I had planned on a Performer EPS intake, but it only has power to 5500, should I go with a Performer RPM?

 

Mark, is this car going to be your daily driver? If you go much bigger than the xe268 your mileage will suffer. I haven't had my car to the strip yet so I can't tell you what it'll run. I think the Holley street dominator would be a better choise for manifolds, they are duel plane now. For a street car with occational strip time, I wouldn't go with the 202 valves, I didn't. If you start turning much over 6000 rpm you'll have to have more than a stock bottom end too. I built a potent street car, not race car.

 

Yes, this will be a daily driver, but for now I figure I can manage 15mpg and be happy, so you think any higher than the 268 will be too much. Thanks for the input, anyone else?? I would like to get the car running as fast as possible without touching the bottom end and dropping more than 3mpg.

 

Mark I can't remember, but I believe you'll have to cut the spring pockets if you go any larger than the 268. I wish I had gone with the 274, myself. But I'm running the stock tpi parts, ported. Are you running the computer dist? Timing will also be a battle, if you're running a vaccum hei dist. I worked on my 77 T/A for about 2 weeks getting the bugs out of it. Had a lot of spark knock, and I'm only running about 9.1 compression ratio on it. I was planning on my GTA for a carb, and my buddy talked me out of it. Have you called comp cams help line yet? Mormar rode in my car last weekend, ask him what cam he is going to run. The xe268 has a pretty good lope to it, even at 750 rpm idle.

 

I am no longer using the ECM, and I'm not the most mechanically inclined person though luckily I have my brother. I definately want a cam with a lope, I wasn't aware the 268 had one. But I figured while I'm doing all this I would try and get the most HP I can while everything will be apart.
Thanks for all your help so far.
Oh, guess I forgot one thing, what kind of compression should I aim for, higher= more HP , but more expensive gas, plus in a few years I wouldn't mind some boost so I would want lower compression. Of course, would my stock bottom end handle some boost? if not I'd have to retake the heads off so I could go with higher compression now and then lower it right?

 

Don't really know anything about boost, have never used it. I DO know that the more compression you have the tuffer time you WILL have tunning it for the street. I'm not trying to talk you out of a bigger cam or anything, I just wanted you to beware that tunning is going to be harder. What heads does your engine have? I hope it's not the swirl ports, only half of the intake ports that regulars have. I'll try and get you a sound file tomorrow and email it to you.

 

RB83L69 said the heads I have now are "meaty" they just need porting, I can get the specs for you in a moment, thanks for the compression tip, I definately want something that doesn't need tuning weekly.

Here's the specs on the motor, and notice the * note about the dyno testing.
Horsepower¹:
249 HP @ 5,000 RPM
Torque¹:
304 FT/LBS @ 3,500 RPM

Redline:
5,200 RPM
Comp. Ratio:
8.50:1

Heads:
Cast Iron, 72 cc
Valves:
1.940" I, 1.500" E

Camshaft Lift:
Hydraulic; 0.390" I , 0.410" E
Duration @ 0.050":
195° I, 202° E

Block:
4 Bolt Main, 2 Piece Rear Main Seal, 4.000" Bore

Crankshaft:
Cast Iron Nodular, 3.480" Stroke

Spark Plug:
R44TS, Gap @ .035 For Points Distributor or .045 For HEI Distributor

Note¹ - Numbers are for a engine that had a cast iron intake, Q-Jet Carb., HEI distributor, 1-5/8" headers and open exhaust installed prior to dyno testing.

 

Mark, I think I'd look for some tpi l98 heads. Something with 64cc chambers, need to get the compression up to use the 268 or the 274 cam. Call comp cams to be sure though. I'm running about 9.6.

 

I am kind of on a budget and was hoping to settle with porting the heads I have now, if it's a must, I'll pick up some heads further down the road. I figure with the cam, TC, heads, intake, that's going to run me about close to $750 right there with gaskets and such. So that's going to be pushing it for me, I'm in college so money isn't flowing in like it used to, but I figure by next summer hopefully I'll have what I want.

 

Mark, you will have to change the springs, for allmost any cam swap. There is a guy on ebay, that sells springs for the old Z28s of the late 60s. They will work on your stock heads, but the 268 is the limit on them. The 274 takes a differant set. Go look at auction 1820686554. I used these on my engine, they work good.

 

if you use varibale duration lifters you can go with a much bigger cam, before I put my heads and EFI on I had a edelbrock 600 cfm carb, OLD (70's era) heads and a wiend intake, and the same cam I have now (comp cams 280H 230* @.05 lift)and it was verry streetable, I got decent gas milage (15-20mpg) and the only thing ristricting the power was the exaust, wich was stock(not even headders ) just my .02

 

Cool, thanks.

 

my buddy has a 268xtreme cam in his 383 and the thing lopes like crazy, and my other buddy has a 274xtreme in his 455 and it sounds like a full out drag car.

 

Just putting in my 2 cents...

Mark, you might want to think of some more machining to your heads other than the porting if they are going to be on the benchf for a while and out of the car. Shaving the deck will increase the compressing and flatten out the surface so that the gasket will seal better. Also maching ing for bigger diameter
valvesprings may or may not work in your favor.

A valve job will go a long way with your bro's porting. With that you my want to get some swirl polished valves. This will go a long way to help the flow and your brother can hog out the bowl to the 85-90% of the valve size, and then your flow will really increase!

Also, getting a flow test done on the heads will help you, o the desktop dyno, or Comp, choose your bumpstick and/or torque comverter...

Tell me if that helps at all!

 

I just talked to my brother and he said with my budget, to keep my stock valves 1.94/1.5 for now. He's going to port them and he said something about sending them off to bump the compression just a bit.
And probably I'm going to go with the Comp 274XE, this won't affect my power accessories to much will it? And probably a 2500-2600 stall TC.
Will I have to get new springs with that cam, which I was looking at, they're not that expensive.

On Desktop Dyno with 9.0 compression it gets me around 348HP @5500 rpms and 377TQ @4000 rpms, does this sound streetable to anyone?

 

IMO, the 268xtreme is the biggest i would run, just from what I have read about them. I know hot rod did a junkyard build up with a 268xtreme cam, stock heads that had a 3 angle vavle job and minor bowl work with 8.5 compression and got 330hp. The 274 is kinda big for a daily driver IMO, and I think that you would make more tourqe in a better RPM range with the 268xtreme and wouldnt have to run as big of stall. again, just my .02