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Author
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Topic: Heads and cam combo...
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H8CHEVY
Gearhead Posts: 200
From: Southern Cali
Registered: Jun 2000
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posted 09-01-2001 04:03 PM
   
Alright guys my friend is going to get an engine built, 302 to be exact. We want to make the most horses from a 302 short block. The compression we are aiming for is about 10:1, and he wants to know what is the best head and cam combo. He knows that the intake will be a Victor jr., and the carb is undetermined too. He has a 5 speed with 3.70 gears.. So can you guys give us your input and suggestions towards this engine???
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chips67
Gearhead Posts: 537
From: louisville, ky, usa
Registered: Jul 2001
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posted 09-01-2001 04:32 PM
afr 185's with an xe282 comp cam. have the rods set up for arp bolts and get pistons with enough valve relief for that cam and 2.02 valves. this motor is said to make 455hp and close to 400ft lbs of torque. actaully read it in a few magazines. is that enough hp?------------------
67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.78 60ft. time.
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jdsgallops
Gearhead Posts: 285
From: Green Bay, WI
Registered: Feb 2001
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posted 09-01-2001 11:01 PM
What year and model car will it go into and what year block is he using?
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H8CHEVY
Gearhead Posts: 200
From: Southern Cali
Registered: Jun 2000
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posted 09-03-2001 06:50 PM
Its an 83 mustang, its gutted and will have absolutly nothing for smog, no heater, no a/c... not to be a daily driver...
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jdsgallops
Gearhead Posts: 285
From: Green Bay, WI
Registered: Feb 2001
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posted 09-05-2001 06:23 PM
Hey that sounds like my car! What year block does he plan on going with. That will detrimine if it can be flat tappet or roller.------------------
83 Gt W/ used gt-40 headed long block, 125 shot of nitrous and a broken tranny
97 F150 daily driver
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H8CHEVY
Gearhead Posts: 200
From: Southern Cali
Registered: Jun 2000
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posted 09-05-2001 08:21 PM
well, he throw a rod and the block has a huge crack in the cylinder walls too. so that block is trash, so he was gonna get one from a junk yard.. what year do you suggest???
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JAAZZY
Gearhead Posts: 666
From: Bay Area, CA
Registered: Apr 2001
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posted 09-05-2001 09:46 PM
Get a roller block. I think that is 87 and up. I don't know much about the late model cars. I just purchased one new and they really aren't expensive. Summit has them for $299. Don't overlook the TFS heads. You can probably find a set somewhere used for not much money. The AFRs are basically factory ported. The Edelbrock heads work well also. The reality is that the combo is more important than the brand. I have TFS Street Heat heads(high port) in my 65.
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jdsgallops
Gearhead Posts: 285
From: Green Bay, WI
Registered: Feb 2001
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posted 09-06-2001 12:23 AM
Well HMMMMMM. As far as block goes, if he plans on turning any kind of serious rpm the earlier block would be better. If going with the late model roller block you are basicly limiting yourself to 6000-6500rpm. The hydro roller lifter won't do much more than that. So using an early block I would look at a cam with high 230 duration and 6-8 more degrees on the exhaust. Lift will be as much as possible if you are using a good set of heads. Aim for 110 or 112 lobe seperation if possible on a street driven car. As far as heads go I have been partial to Canfields. They seem to have very good flow numbers for the size they are. Unfortunately I have heard of too many intake problems with these heads. Ports not lining up has been quite common. I have turned into a Trick Flow fan because of this. The trick flow head has a relatively small runner(170cc) and will flow real well. Total engine airflow in bowling green Ky, is getting [email protected] lift with these heads. That is some serious flow, enough for 600hp. Either way any aftermarket head will get you over 350hp with the right cam and intake. From what I have seen the 302 likes a cam in the high 230 range. It will pull to 7000rpm and put a smile on your face.[This message has been edited by jdsgallops (edited 09-06-2001).]
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JAAZZY
Gearhead Posts: 666
From: Bay Area, CA
Registered: Apr 2001
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posted 09-06-2001 12:18 PM
My early 289 block(67 I think) was great and it did rev nicely up to 7000rpm. I stroked my new roller block(347) and it revs nicely up to 6500. I think you can safely move the rpm up 500 on the newer blocks with a stud girdle and a good set of rods and pistons. Obviously to go more radical I would have gone with an SVO block but I think it isn't necessary until you go over 550hp.
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jdsgallops
Gearhead Posts: 285
From: Green Bay, WI
Registered: Feb 2001
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posted 09-06-2001 12:42 PM
Jazzy the problem with the stock roller lifter is weight. Many test's have been done and all show that the lifter floats the valves between 6500and 6600 rpm, almost regardless of spring prssure. This is why comp cams has come out with the lightweight roller lifter. It is fairly pricey though, in the $300 range for a set.
On a side note just because your engine will rev to a certain rpm doesn't mean it is making any more power there. On my old 302 I could take it to 6500 also. Unfortunately my best times came shifting at 5700. 6000rpm slowed the car down also. IMO a 347 roller block at 6500 isn't going to last real long. Then again I am no pro engine builder so what do I know.
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68Mustang
Gearhead Posts: 166
From: Auburn, AL
Registered: Feb 2001
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posted 09-06-2001 01:23 PM
Yeah, one of my friends continued floated valves at about 6600. Still don't understand what the weight of the lifter has to do with it, maybe someone will explain????Marshall ------------------
1968 302 5-spd Fastback, Modified
1965 Coupe
1981 F-150
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JAAZZY
Gearhead Posts: 666
From: Bay Area, CA
Registered: Apr 2001
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posted 09-06-2001 01:32 PM
I wasn't really arguing with you and maybe you are correct that the 347 won't last all that long at that rpm. I don't really know. Actually I was just making a point. I would probably shift this motor at about 6300-6400rpm. It seems like it pulls really hard to 6200 and then starts to let up a bit.Honestly, I just got this thing running and don't have enough time in it yet for long term opinions. I still have a few bugs to work out before I run it at the track. I wish I had known about the lightweight lifters before. It would only have been a little more money. BTW, Probe/Coast seems to think that the motors can take the rpm. Offcourse you can't always believe the seller. I'll know soon enough.
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jdsgallops
Gearhead Posts: 285
From: Green Bay, WI
Registered: Feb 2001
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posted 09-06-2001 02:08 PM
quote:
Originally posted by 68Mustang:
Yeah, one of my friends continued floated valves at about 6600. Still don't understand what the weight of the lifter has to do with it, maybe someone will explain????Marshall
The weight helps determine the amount of spring pressure you need. The more weight you have to control the harder it is to control it. Since a hydraulic lifter is filled with oil, then add the roller assembly, and lifter bars, you have a considerable amount of weight to control, compared to say a mechanical lifter. Upping spring pressure may help valve float but is going to more than likely hurt low end power (from the added spring pressure) and shorten valvetrain life.
[This message has been edited by jdsgallops (edited 09-06-2001).]
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68Mustang
Gearhead Posts: 166
From: Auburn, AL
Registered: Feb 2001
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posted 09-06-2001 02:38 PM
I went into deep thought on the subject and realize that the force of gravity has no signifigance at high rpm's and that the lifter will want to do exactly the opposite of what is expected. Therefore the less force you have to exert to move the lifter the more power, basically the whole premise of building an engine. Less parasitic loss is a great, great thing.Marshall ------------------
1968 302 5-spd Fastback, Modified
1965 Coupe
1981 F-150
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