JoeinCA Posted November 25, 2001 Share Posted November 25, 2001 ok, today i went through and identified via casting numbers, the cylinder heads, the block, and my intake manifold... The engine is a i968 327 engine, rated at a whopping, disheartening 210 hp. the cylinder heads are applicable for 307s and 327s in 1968.although they have the double hump markings as well. I have a 4 barrel intake manifold off of a 74-76 camaro on it. i dont have any info on the cam, so i assume it is stock, as well as the pistons. so, how much of a difference could i make by changing the intake manifold, the cylinder heads, and the cam? I am planning on running a 600-800 CFM edelbrock 4 bbl. I am shooting for around 300-350 HP . can anyone lend some advice? thanks for your time. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted November 25, 2001 Share Posted November 25, 2001 Joe, All the HP potential is in the heads, cam and intake, so good choices in these areas could easily make 300+ hp. Tim Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 25, 2001 Author Share Posted November 25, 2001 right tim, which is why those are what i listed as to what i wouyld replace, in order to not waste my money on things that wont show large gains. What i am wondering, is if there are stock heads that i should keep an eye out for at junkyards, or what heads are recommended to use, under $500 complete. And what cams are good for street use in the heads that are recommended, good combos and such... to tell you the truth, i only have rudimentary knowledge of cams and head combos. Which is why i asked, because a suggestion will give me a starting point to begin researching different parts, so that i know what is good and what isnt. sorry if your getting annoyed at seeing yet another post asking about how to improve performance in small block chevy engines. But that is the point of this forum, powerful engines in Z cars. Or if i am way off about that, then sorry, and thanks for your input. Quote Link to comment Share on other sites More sharing options...
Mike C Posted November 25, 2001 Share Posted November 25, 2001 What is the casting number of your heads? (Between some of the rocker studs with the valve cover off) Any of the "double humps" are good heads. I would recommend hardened exhaust seats, new bronze guides and 2.02 1.60 valves be installed. Vatting and surfacing and a simple pocket port and port matching will make those heads flow very well. I highly recommend David Vizard's book, "How to build and modify small block chevy cylinder heads", very well worth the $25. He shows how to get a set of double humps to flow 260 cfm on the intake at .550 lift. Compareable to the AFR 195 which win most of the streetable head comparisons. I have a set of ported 492 on my 355 and they push my 3500# Camaro to the mids 12's at over 110 mph on street tires through the mufflers. Check out Northern Auto Parts for a $450 rebuild kit with all new parts and forged pistons. (I recommend the Energizer 272 cam for your setup.) Also, save up a few extra bucks for an aftermarket aluminum intake. Either the Weiand Stealth, Holley 300-36 or Performer RPM. Check out these guys also for some discount parts:Powerhouse Engine Kits Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 25, 2001 Author Share Posted November 25, 2001 the cast numbers on the head are 3917293. thanks for the advice, i was told that the engine was rebuilt before it was stored, but as with everything else i was told about the engine, it may be false. the intake is at 1.72, and the exaust is 1.5. thanks for the help again, i will make sure to check that site out. with the parts you suggested, roughly, what kind of Hp do you think the engine might put out?... With the edelbrock intake. I'll check the compression, and pull the heads and see what kind of condition the cylinder walls are in to see if it needs a rebuild. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted November 25, 2001 Share Posted November 25, 2001 Joe, I am using, and am very happy with, the Vortec heads available from GM. Fully assembled and new are less than $500.00, and flow better than most aftermarket heads, and the vette heads. For a little more you can get them with the upgraded springs for a 'bigger' cam, that's brings them up to just over $600. Well worth it. I got mine from Scoggin Dickey. Only downside is the weight of the cast iron vs. the Aluminum aftermarket heads, but the price makes it well worth it. An article in Super Chevy, or Chevy High Performance (???), made 409HP with these heads. Tim Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 25, 2001 Author Share Posted November 25, 2001 i thought i had heard some good things about the vortecs... What cam are you runnign and what kind of horsepower are you getting? thanks tim, i'll look into those vortecs. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted November 25, 2001 Share Posted November 25, 2001 Joe, Have a look at the post "desktop Dyno revisted" in this section. Tim Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 25, 2001 Share Posted November 25, 2001 The other downside of vortec heads(unless I'm mistaken) there isn't a huge manifold selection. Theres like Edelbrock and GM and thats about it (so far). They do flow great for the dollar its hard to beat for cast iron heads. If you can find some 2.02 double hump heads(or use the vortec heads) with a good manifold (dual plane most likely at that hp level) with say a 650 edelbrock carb (if thats your preference) and maybe like a Comp cams 268H or 270H cam and you should have no problems getting to 300-350 hp. Check your compression ratio too (you'd probably want like 64cc heads), as it'll help with those cam grinds to have 9.5 - 10-1 compression. This is one way of doing it anyway. I'm sure others will weight in with they're opinions as well, but I don't think its hard to get 100-150 hp increase on a SBC just by improving the heads, cam, carb and using headers. Good luck with it! Regards, Lone Quote Link to comment Share on other sites More sharing options...
fl327 Posted November 25, 2001 Share Posted November 25, 2001 the 210hp 327 is a great candidate for nitrous. Quote Link to comment Share on other sites More sharing options...
fl327 Posted November 25, 2001 Share Posted November 25, 2001 sounds good to me, heard good things about the vortec heads. Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 26, 2001 Author Share Posted November 26, 2001 i tore the engine down , removed the heads, and found... bad rust in two of the cylinders. the engine wont turn over, it was rebuilt, and appears to be a racing engine, the pistons are almost flat, and there are three different size markings among the pistons, the crank is marked for somehting about .30, i have a feeling that it was balanced and blue printed at one point.. a shame. I am going to try to salvage it without further boring it though, i dunno, i'll have someone who is good with chevy engines take a look at it and see if he can figure a way to salvage it. in any case, it didnt look completely stock in there and was freshly rebuilt. Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 26, 2001 Author Share Posted November 26, 2001 i am planning on running a 100 hp shot of nitrous.. but i still think it would benefit from improving the flow and bringing it up to 300-350. besides, then i can have alot of power at all times and not have to go fill up the bottle once a week. so far i am considering running the vortec heads, with a comp cams 268, edelbrock dual plane manifold, and an edelbrock 650 CFM carb, or a q-jet... hmm i dunno. Quote Link to comment Share on other sites More sharing options...
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