Thread: 383 build questions

Tweet

Mines Eagle, Flat tops , E-Brock Performer 70 cc heads ,XE274 and no problems on 91, Never dynoed
Has a 3000 Converter and 410s, 2400 and 342s did not work

Thanks again. Hey rumrumm, which intake and carb did you go with?

Originally Posted by contentsunderpr

Thanks again. Hey rumrumm, which intake and carb did you go with?

I have an Edelbrock Performer RPM intake and an Edelbrock 750 carb. In addition, I used an MSD distributer with a MSD 6A ignition box.

Thanks alot.

Did you go with the hydrualic flat tappet cam? What ratio rockers did you use?

Also, I see I have a choice between angled or straight plug holes. Does it matter which one I go with?

The 280 Magnum is a flat tappet cam [.480 inch lift; 230 degrees duration], but if I had a roller block, I would have gone with the roller version. As far as the heads go, get the straight plugs. The angle plug heads will create problems with headers. The AFR 190 heads that I have are no longer available, but I would recommend the new 195 heads for a 383. They are not cheap but they are worth every penny. Their new design is the best available and they produce gobs of hp and torque. Check out their website.

The 195s are the ones I was looking at. How do I know if I have a roller motor or not? I plan to use the flat tappet cam your talking about since it's way cheaper than the roller. The cam says it has an advertised duration of 280. That is the right cam correct?

Yup! 12-212-2 is the cam number.

Thanks again.

ok now i too am building a 383 motor, i have had a bad experience with a low compression motor before. i have done a lot of research and found that compression truly is power. i am currently building an eagle short block with flat tops and 62cc chambered TFS heads. with my gasket and a .060 over bore i will have just over 11.5 to 1 compression, BUT i am at over 4000 ft. elevation AND have aluminum heads.....i figure this to be around a 10 to 10.25 sea level engine. Although there are guys here that do run 12 to 1 engines with cast iron heads on the street, but they are very experienced tuners. anyway i talked to a few circle track guys and they said that for what they do....full throttle 90% of the time.....that the higher the .050 duration and lift figures, the more power you will make, AS LONG AS your intake closing point isn't way too radical. because that is what determines your DCR. and the advertised duration is what determines your rpm range. now there are obviously limits with what you can do with drivabilty, clearances, and durability of a "street" motor because for example, if you push your cam to it's limits you will wear out springs dramatically. but me, i live 3 miles from work and performance is 100% what i'm after. therefore i will probably pick a cam with about 250 to 260 degrees at .050 with a slightly wider lobe separation, probably around 114. and i do plan on running nitrous through this motor too.

now the math and theories are all there to support what should and shouldn't be done, but there are those exceptions. there is a Box nova club around town that runs mid sized small block all day everyday as daily drivers with automatic trannys with mid 260 @ .050. but those are very built cars to say the least, with traction and lightening them up. but they are street legal and they use them.

so don't be afraid to try something new or different or push the limits. i mean what's a cam change.......200 bucks and an afternoon?

also i will use a solid flat tappet with my motown intake and tfs 195 heads pocket ported, a proform 750 should be fun.

All this is a big help guys. How much power do you think a 700R4 can handle without being built?

Originally Posted by contentsunderpr

All this is a big help guys. How much power do you think a 700R4 can handle without being built?

I would not run more than 375 ft. lbs of torque through a stock 700R4. You really should have it rebuilt with extra clutches, Corvette servo, etc. by an experienced tranny man if you are going to run behind a built 383.

Ok. The tranny has been rebuilt. It had 10,000 miles on it when I bought the truck but the guy that built the truck is dead. His son told me it had been built but don't know which shop he used. It did have a corvette governer in it but I swaped it out because the motor that's in it now won't turn enough rpms to shift the tranny. He may have had the better clutchs put in it when it was built but I don't know for sure. My plan is just to chance it and run it till it blows. The reason I was asking though is because I can get my hands on a TH350. I found a guy that will trade me straight up. I really hate to lose my overdrive though since I'll be driving this truck a lot.