steve dalla

well im building a big motor this time!!! i think im going to buy the Econo 427 shortblock from Shaffirof, its 3795. i will be using my lightly used AFR195 eliminator heads for this build. they are stock with 2.05 valves. What kind of cam specs should i be running? car is driven very little and just having fun at test and tune. car has 3100 race weight, 3000 stall, 3.73, 26in M\t slick. it will need to be a small base cam im sure. i dont want to rev motor past 6000 given small heads and hopefully it will live longer that way thanks.

MotorHead

Comp Cams XR280R solid roller get it custom made on small base circle with pressed on iron gear

I would use bigger heads and bigger cam, if you are going with a brand new short block why not do it the best way. Mine will rev to 7500RPM but I don't need to rev it that high if I don't want to but it is there

C3 Stroker

Agree with above.....you're leaving 50 HP on the table by not using larger heads, but the XR280R is a good choice for your combo.....you will have a somewhat mild lope and lots of torque.

steve dalla

i know its not ideal but im workin with about 5000 bucks and i can always get bigger heads later. the shortblock is my big purchase for now. even though these heads are better suited for a 383, there is no way in hell that the 427 wont make way more power even if its ckoked by the heads right???? Motorhead did you ever figure out if we can buy a set of those nice headers you had made? if not what should i use? thanks

63mako

That short block is advertised with 13 to 1 pistons. I wouldn't go there. Need to know head CC, piston to deck height, gasket bore and compressed thickness to accurately figure correct piston to use to get your compression down. Those heads flow pretty good. I think they will pull good to 6000 RPM and since you already have them I would use them. If your limiting RPM to 6000 I would keep compression to under 10.5 to 1. I would go Hydraulic roller for durability and less maintainance. If you had bigger heads and planned on 7000 RPM a solid roller is the way to go and the cam above is a great option. This HR cam has good duration and lift to help get the most out of your heads. It is radical in a smaller engine but with 427 CI It should do what you want, be a good match for your heads, convertor, gears and intended RPM. The operating range will drop some in a 427 and that many CI should have enough torque to run 3.73 gears fine.
http://www.compcams.com/Cam_Specs/Ca...?csid=182&sb=2
This is for the OEM roller. Add Billet, small base circle, pressed on iron gear. Those heads have lightweight valvetrain components and quite likely beehive spings good for .600 lift but check them to be sure. This should give you the capability to run 6500 RPM shift points with no valve float issues and you might not have to change springs.

steve dalla

i talked to Shaffirof and they said they had a 20cc dish that they could use. it is a coated mahle piston and they want 200 more$ for the set. i have 65 cc heads. can anyone tell me what that works out to.?

MotorHead

Those are probably the Mahle pistons I have, get the part number but pretty sure you will end up with 10.6:1 or so because there are not many pistons that are available for a small block 427. Wiesco makes a 427ci small block pump gas piston too. With that cam you can slap on a set of bigger heads later and you will get around 600+HP.

The headers are going to be made but I do not know when. They said they have too much on there plate right now

steve dalla

can i use my straight plug heads with the headers you have?? also i think i saw that you used to run the hooker super comps, do you know if they work with straight plugs? what kind of power would you guess with my smaller heads and your cam? thanks

MotorHead

Those heads have smaller runners but flow pretty good numbers, properly setup with the rest of the parts correct you should make 500 -550HP or therabouts, use Hooker Supercomps with the 1 3/4" primaries. I can't tell you the headers will work without dinging them with either angle or straight plugs, you buy them and ding them

63mako

Those 195 heads flow about 290 CFM @ .600 lift with a 4.125 bore. If your engine is properly designed I bet 550 to 575 HP and similar torque is realistic.

BTW. The flow numbers on these are better than a Dart 23 Deg 220-225 Super Mod Alum head with 225 CC intake ports and 88 CC exhaust ports. The AFR eliminator heads have a 195 CC intake port and a 64 CC exhaust port.

eagle275

gkull

My original Bill Mitchell 427 small block came with 64 cc AFR 210 heads, 20cc dished good for maybe 10.4 compression. It had the Comp XR294HR cam with 1.6 steel RR's Weiand 7531 single plane

I had a higher stall 700R4 with 4.11 and it ran pretty good. Mild lope.

Your newer 195's flow as much as the old 210's Bill M sold it as their 550 hp street machine or something engine.

63mako

The cam specs on the intake side of the XE294 HR are very close to the HR I recommended after you figure the lift and duration increase from the 1.6 rockers except it is a split duration cam. I figured with the intake exhaust ratio of the AFR eliminators you could go with a single pattern cam. I never usually recommend a single pattern cam but the ratio is pretty high on these heads compared to most and it gets you .600 lift with regular 1.5 rockers.
The solid cam Motorhead posted is real similar in lift and duration @ .050 also. I didn't even look at it before I posted. It is a tight lash cam and has a faster ramp. You will lose a little true lift and duration because of the lash but the faster ramp will make a little more peak HP. Trade off is stiffer springs needed to deal with the solid roller fast ramp and periodic valve adjustments and lifter checks. All three of these cams would be similar in power and torque with similar operating ranges. Bet they are within less than 5% across the operating range.

gkull

I should add that I never ran it like it was sold. I was just giving a dyno 550 hp comparison. The whole idea of H-rollers and rpm limitations bothered me. I called comp cams about the feasability of running Solid rollers on a h-roller. The answer was no problem if I ran a tighter lash spec like I .010 & E .012. Also the low lift numbers bothered me so I used 1.65 rockers on the intake 1.6 on the exhaust.

It actually had enough TQ that you better have a good tranny and my 315 rear tires could leave some long twin wide black marks from a rolling 25 mph in second gear by just flooring it.

63mako

Here is a cam for you. Same cam Gkull had in his 427.
http://forums.corvetteforum.com/c3-p...at-prices.html

MotorHead

Why steer him away from a solid roller ? That is the only cam I would ever put in a motor I built. With my shaft rockers I haven't had to adjust them after the first 500 miles. I don't even worry about them any more.

63mako

Only because of his initial post saying he was limiting RPM to 6000 RPM and using heads that will probably not support 7000 RPM plus in a 427. Seems like a good match for a hydraulic roller although I would use the other one I posted but he is on a limited budget. This cam is $150

MotorHead

$150 for a roller cam or flat tappet ? You are probably correct but I really like solid rollers, they are the top of the heap and the maintenance is not nearly as bad as some think. GM even made production vehicles with solid flat tappet cams.

Anyway in this case because of the limitations I am inclined to agree with you

Would like to see someone use that 280 Magnum HR some day

63mako

The link is this:
Brand new never opened comp cams rollers XR294HR @ .050 lift 242/248 duration with .54/.562 lift. This cam has a small base circle and is recommended for 383 sbc. Cam comes with factory warranty registration card. I am selling this cam for half price just to get rid of it $150. I don't know if it the step nose or the retro roller. The earlier cam I linked has similar duration and .600 lift. I like the solid roller you recommended. Looks good with good exhaust flowing heads like the AFR's if your pushing high RPM.

MotorHead

Now that's a good buy !